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3462 Federal Register / Vol. 57, No. 19 / Wednesday, January 29, 1992 / Rules and Regulations

ENVIRONMENTAL PROTECTIONAGENCY

40 CFR Parts 260, 264, 265, 270, and

271

[FRL-4028-2]

RIN 2050-AA76

Liners and Leak Detection Systems forHazardous Waste Land Disposal Units

AGENCY: Environmental ProtectionAgency.ACTION: Notice of final rulemaking.

SUMMARY: The Environmental ProtectionAgency (EPA) is today amending itscurrent regulations under the ResourceConservation and Recovery Act (RCRA)concerning liner and leachate collectionand removal systems for hazardouswaste surface impoundments, landfills,and waste piles. EPA is also adding newregulations requiring owners andoperators of hazardous waste surfaceimpoundments, waste piles, andlandfills to install and operate leakdetection systems at such time as theseunits are added, laterally expanded, orreplaced. EPA is promulgating most ofthese regulations in response to therequirements of the 1984 Hazardous andSolid Waste Amendments (HSWA) toRCRA.EFFECTIVE DATE: July 29, 1992.ADDRESSES: The public dodket (docketreference code F-92-LLDF-FFFFF) forthis rule is in room M2427, US EPA, 401M Street SW., Washington, DC 20460,and is open from 9 am to 4 pm, Mondaythrough Friday, excluding holidays. Call202-260-9327 for an appointment loreview docket materials. Lp to 100pages may be copied free of charge fromany one regulatory docket. Additionalcopies are $0.15 per page.FOR FURTHER INFORMATION CONTACT:The RCRA/Superfund Hotline at 1-800-424-9346 (toll free), or 703-920-9810 inthe Washington, DC area. Forinformation on technical aspects of thisrule, contact Ken Shuster, Office of SolidWaste (OS-340), U.S. EnvironmentalProtection Agency, 401 M St SW.,Washington, DC 20460, 202-260-2214.SUPPLEMENTARY INFORMATION: Copiesof the following documents are availablefor purchase through the NationalTechnical Information Services (NTIS),U.S. Department of Commerce,Springfield, VA 22161, phone 1-800-553-6847 or 703-487-4650: (1) U.S. EPA,-'Compilation of Current Practices atLand Disposal Facilities", January 1992;(2) U.S. EPA, "Action Leakage Rates forLeak Detection Systems", January 1992.

Preamble OutlineI. Authority11. BackgroundIll. Summary of Today's Rule

A. Summary of RuleB. Achievement of EPA Program Goals

IV. Detailed Discussion of the RuleA. Scope of the RuleB. Standards for Liners and Leak Detection

Systems1. Technical Standards for Liner Systems2. Technical Standards for Leak Detection

Systems3. Alternative Systems4. Applicability to Waste Piles5. Applicability to Land Treatment UnitsC. Response to Leaks1. Action Leakage Rate2. Response Action PlanD. Monitoring and Inspection RequirementsE. Construction Quality AssuranceF. Implementation of Permitting and

Interim Status RequirementsV. State Authority

A. Applicability of Rule in AuthorizedStates

B. Effect on State AuthorizationsVI. Regulatory Requirements

A. Economic Impact AnalysisB. Regulatory Flexibility ActC. Paperwork Reduction Act

VII. Supporting DocumentsList of Subjects

I. Authority

These regulations are beingpromulgated under authority of sections3004, 3005, 3006, and 3015 of the SolidWaste Disposal Act, as amended by theResource Conservation and RecoveryAct, as amended, 42 U.S.C. 6924. 6925,6926, and 6936.

U. Background

On November 8, 1984, Congressenacted the Hazardous and Solid WasteAmendments (HSWA) to the ResourceConservation and Recovery Act(RCRA), placing stringent newrequirements on the land disposal ofhazardous waste. Among otherrequirements, Congress amendedsection 3004 of RCRA and added section3015 to impose specific design standardsfor land disposal units.

Section 3004(o)(1)(A) of RCRA, addedby HSWA, requires each new landfilland surface impoundment, and eachreplacement and lateral expansion of alandfill and surface impoundment forwhich an application for a final permitdetermination is received afterNovember 8, 1984, to install two or moreliners (i.e., a double-liner system) and aleachate collection system above [forlandfills) and between the liners.Section 3004(o)(5)(A) of RCRA requiresEPA to promulgate regulations or issuetechnical guidance implementing therequirements of section 3004(o)(I A) byNovember 8, 1986. These HSWArequirements for double liner systems

are intended to prevent the migration ofhazardous constituents to ground waterfrom land disposal units. Until theeffective date of regulationspromulgated under section 3004(o)(5)(A),Congress provided that an interimstatutory double-liner standard insection 3004(o)(5){B) could be used tomeet the section 3004(o)(1)(A) double-liner system requirement.

Section 3004(o)(4) of RCRA requiresEPA by May 8, 1987, to promulgatestandards requiring new landfills,surface impoundments, waste piles, landtreatment units, and undergroundhazardous waste tanks to use approvedleak detection systems. The statutedefines an "approved leak detectionsystem" as a system or technology thatEPA determines to be "capable ofdetecting leaks of hazardousconstituents at the earliest practicabletime." The term "new units" is definedas those units on which constructioncommences after the date ofpromulgation of the Agency's rule forleak detection systems. The impact ofthis language upon the applicability ofthis rule between today's promulgationand the effective date July 29, 1992 isdiscussed elsewhere in this preamble(See Section IV.A.).

Section 3015(a) of RCRA establishesstandards for interim status waste piles.Any new waste pile, or replacement orlateral expansion of an existing wastepile at an interim status facility, mustcomply with requirements for liners andleachate collection systems orequivalent protection provided inregulations issued by EPA under section3004 of RCRA before October 1, 1982, orrevised under section 3004(o) of RCRAwith respect to waste receivedbeginning May 8, 1985.

Section 3015(b) of RCRA establishesstandards for interim status surfaceimpoundments and landfills. Any newunit, or replacement or lateral expansionof an existing unit at an interim statusfacility, is subject to the requirementspromulgated under section 3004(o)(1)(relating to double-liners and leachatecollection systems), with respect towaste received beginning on May 8,1985.

The HSWA requirements describedabove either directly amended ordirected the Agency to amend theexisting RCRA liner standards for newhazardous waste landfills, surfaceimpoundments, and waste piles issuedby EPA on July 26, 1982 (47 FR 32262).On July 15. 1985, EPA issued a final rule(50 FR 25702) amending the existing linerstandards by codifying the new linerstandards of sections 3004(o)(1)(A),3004(o)(5)(B), and 3015 (a) and (b) that

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Federal Register / Vol. 57, No. 19 / Wednesday, January 29, 1992 / Rules and Regulations

were to become effective immediately orshortly after the enactment of HSWA, asdirected by the statute.

On March 28, 1986 (51 FR 10706),under section 3004(o)(5)(A) of RCRA,EPA proposed amendments to thestatutory double-liner and leachatecollection system standards for surfaceimpoundments and landfills codified inEPA's regulations on July 15, 1985. Theproposal set forth two types of designsfor double-liner systems. One designconsisted of a geomembrane (thenreferred to as a flexible membrane liner(FML) as the top liner and a compositebottom liner consisting of ageomembrane underlain by compactedsoil material to minimize flow throughthe geomembrane component should abreach occur, and having a hydraulicconductivity of no more than 1X10- 7

cm/sec. The other proposed double-linerdesign consisted of a geomembrane topliner and a bottom liner constructed toprevent migration through the linerthrough the post-closure period and of atleast 3 feet of compacted clay or othercompacted soil material with ahydraulic conductivity of no more than1X10- 7 cm/sec. On April 17, 1987, EPApublished a notice (52 FR 12566)requesting additional comments oncertain aspects of the March 28, 1986proposal. Specifically, EPA requestedcomments on data that demonstratedthe advantages of a composite bottomliner versus a compacted soil materialbottom liner. EPA also noticed theavailability of two draft technicalguidance documents for the design,construction, and operation of single-and double-liner systems and leachatecollection systems. EPA solicitedcomments from the general public on thedraft technical guidance documents.

On July 14, 1986 (51 FR 25422), EPApromulgated leak detection systemrequirements for undergroundhazardous waste tanks. In promulgatingthese regulations, EPA partially fulfilledits mandate under section 3004(o)(4) ofRCRA to establish leak detection systemrequirements.

On May 29, 1987 (52 FR 20218), EPAproposed a rule establishing leakdetection system requirements to fullyimplement section 3004(o)(4) of RCRA.The proposal specified design standardsfor leak detection systems for new andreplacement landfills, surfaceimpoundments, land treatment units,and waste piles, and for lateralexpansions of these units at bothpermitted and interim status facilities.The proposal also expanded the double-liner requirements to waste piles. Theproposal also included a requirement fora construction quality assurance

program to be implemented by ownersand operators to ensure the properconstruction, installation, and closure ofthese units. Finally, the proposalincluded a requirement to develop aresponse action plan specifying actionsthat would be taken in reaction to liquidflow into the leak detection systemabove action leakage rates proposed bythe owner or operator and approved bythe Regional Administrator.

Today's rule finalizes EPA's proposedactions of March 28,1986 and May 29,1987, and completes the Agency'sstatutory rulemaking responsibilitiesimposed by RCRA sections 3004(o)(4)and 3004(o)(5)(A). EPA has not includedadditional leak detection standards forpermitted land treatment units intoday's rule because, as explained laterin today's notice, existing unsaturatedzone monitoring requirements in§ § 264.278 and 265.278 for such units aresufficient to ensure the detection ofleaks at the earliest practicable time.

Il. Summary of Today's Rule

A. Summary of RuleToday's rule modifies the existing

double-liner and leachate collection andremoval system requirements for newand replacement surface impoundmentsand landfills and for lateral expansionsof these units, including those units atinterim status facilities. New surfaceimpoundment and landfill units forwhich construction commences afterJanuary 29, 1992, and replacement unitsreused after and lateral expansions ofexisting units for which constructioncommences after July 29, 1992 must havea double liner consisting of a top linerdesigned to prevent the migration ofhazardous constituents into the linerduring the active life and post-closureperiod (e.g., a geomembrane) and acomposite bottom liner consisting of ageomembrane underlain by at least 3feet of compacted soil material having ahydraulic conductivity of no more than1X10- 7 cm/sec. EPA is also extendingthe revised landfill double-liner andleachate collection and removal systemrequirements to new waste pile units forwhich construction commences afterJanuary 29, 1992, and replacement unitsreused after and lateral expansions ofwaste pile units for which constructioncommences after July 29, 1992.

Today's rule also requires a leakdetection system for each new surfaceimpoundment, waste ple, and landfillfor which construction commences afterJanuary 29,1992, and each replacementsurface impoundment, waste pile, andlandfill reused after, and each lateralexpansion of these units for whichconstruction commences after July 29,

1992. The leachate collection andremoval system drainage layerimmediately above the bottomcomposite liner at these units must beused as the leak detection system. Thedrainage layer functioning as the leakdetection system must meet minimumdesign criteria and ensure that leaks aredetected at the earliest practicable time.Specifically, the drainage layer bottomslope must be one percent or more. Ifgranular material is used in the drainagelayer, it must have a minimum hydraulicconductivity of 1× 10-2 cm/sec for wastepiles and landfills and 1x10 - 1 cm/secfor surface impoundments and aminimum thickness of 1 foot. If syntheticdrainage material is used in thedrainage layer, the drainage materialmust have a minimum hydraulictransmissivity of 3 X10 - 6 m2/sec forwaste piles and landfills and 3X10 - 4

m2/sec for surface impoundments. Thesetransmissivities are equivalent to theabove hydraulic conductivities andthickness specifications for granulardrainage layers. EPA is requiring thateach unit have a leak detection sump tocollect and remove liquids, sized toprevent liquids from backing up into thedrainage layer. In lieu of meeting theserequirements, the owner or operatormay receive a variance for analternative leak detection system thatfunctions in an equivalent manner.

EPA is establishing a site-specificaction leakage rate that specifies aliquid flow rate detected in the leakdetection system sump that warrantsfollowup actions by the owner oroperator. Owners and operators arerequired to develop a response actionplan specifying monitoring, inspection,and corrective measures to beimplemented if the action leakage rate isexceeded.

The Agency is requiring owners andoperators of units affected by today'srule to develop a construction qualityassurance (CQA} program for variouscomponents of surface impoundments,waste piles, and landfills. The programwill be implemented through aconstruction quality assurance plan thatthe owner or operator prepares toensure that the constructed unit meetsor exceeds all design criteria, plans, andspecifications.

Owners or operators of facilitiesapplying for a permit for new surfaceimpoundments, waste piles, andlandfills must submit information onliners and leak detection systemdesigns, the action leakage rate, theresponse action plan, and CQA plans aspart of the permit application. For newand replacement surface impoundment,waste pile, and landfill units, and lateral

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expansions of existing units at permittedfacilities, owners and operators mustsubmit this information as part of apermit modification request. Foraffected units at interim status facilities,the owner or operator must submitproposed action leakage rates, responseaction plans, and a certification thatconstruction has been completedaccording to the design specifications inthe CQA plan to the Agency in advanceof the receipt of wastes. Liner and leakdetection system designs and CQAplans need not be submitted to EPA, butmust be maintained on site.

B. Achievement of EPA Program Goals

In developing today's rule, EPA paidcareful attention to several principlesthat now guide its environmentalprograms: Pollution prevention, ground-water protection, cost-effective policieswhich provide protection of humanhealth and the environment, flexibilityin implementation, and fostering of aneffective State-Federal partnership.Today's rule incorporates each of theseprinciples.

The primary focus of today's rule is onpollution prevention and, morespecifically, on ground-water protection.Effective liner and leak detectionsystems will minimize the potential forreleases of hazardous constituents fromhazardous waste land disposal units tounderlying ground water. In this way,today's rule complements the Agency'swaste minimization policies, which seekto reduce the quantities of wasteproduced, and the RCRA land disposalrestrictions programs. Today's liner andleak detection standards contribute topollution prevention by providing for thecontainment and isolation of hazardouswaste after final disposal.

In today's rule, EPA has taken animportant step in implementing itsGround-Water Principles, recentlypublished in the Agency's "Protectingthe Nation's Ground Water: EPA'sStrategy for the 1990's (21Z-1020, July1991). A central theme in EPA's ground-water policy, enunciated in theprinciples, is that prevention of ground-water contamination is often more costeffective and environmentally moredesirable than remediation of ground-water after contamination. Experiencein the RCRA and Superfund programsdemonstrates that improperly designedlandfills, surface impoundments, andwaste piles can result in ground-watercontamination. At the same time,remediation of contaminated ground-water has proved to be time-consuming,expensive, and in some casestechnically infeasible. On the otherhand, the release of hazardousconstituents from landfills. surface

impoundments, and waste piles canlargely be eliminated through gooddesign and construction.

Regarding costs, it should be notedthat most of the standards incorporatedinto today's rule are already widely inuse at hazardous waste facilities andare generally considered goodengineering practices. Because HSWArequired new landfills and surfaceimpoundments, and lateral expansionsand replacements of existing landfillsand surface impoundments, for which anapplication for a permit is received afterNovember 8, 1984, and those units ininterim status receiving waste after May8, 1985, to be designed with double-linerand leachate collection systems, mostfacilities already meet many of thedesign standards of today's rule. Inaddition, many facilities have designedunits that are in compliance with today'sfinal rule in anticipation of thepromulgation of a final rule based on theMarch 28, 1986, and May 29, 1987proposed rules. Thus, for a relativelysmall increase in cost (to those facilitiesthat are not already meeting thestandards of today's rule], the rule maysave large corrective action costs.However, since all new units mustcomply with all the provisions of thisrule and bear the corresponding costs,EPA has carefully chosen the minimumtechnical standards that adequatelyprotect human health and theenvironment.

Although today's rule includesspecific design standards, EPA hastaken care to ensure that itsrequirements can be flexiblyimplemented. The presence of specificstandards in the rules will simplifycompliance by the regulated community,implementation by EPA and Statepermit writers, and enforcement by EPAand state c ficials. EPA, however,recognizes, that national designstandards may not be appropriate forevery site and that technologies mayimprove. Therefore, today's rule allowsEPA or an authorized State to approvealternative designs, as long as theyachieve comparable or better levels ofperformance.

Similarly, today's rule requiresconstruction quality assurance-acritical feature in land disposal unitconstruction-but it does so throughgeneral narrative performancestandards. Thus, facility owners oroperators can tailor the details of theirconstruction quality assurance plans tothe specifics of their facilities. Theseand similar provisions of today's ruleensure that the rule can be flexiblyimplemented, in a way thataccommodates each regulated unit.

Finally, in today's rule EPA has paidspecial attention to eliminating thefrequent strains resulting from the jointimplementation of RCRA by EPA andthe States. In proposals for this rule,EPA laid out a complicated Stateauthorization process, which wouldrequire EPA to implement some parts ofthe rule for selected land disposal unitsand the States to implement other partsfor the same units, over differenttimeframes. After radically simplifyingthe proposal, EPA is now promulgatingmost of the rule under HSWA, whichavoids much of the confusion of jointimplementation at individual units. Inthis way, today's rule is consistent withthe Agency's attempt to simplify andrationalize Federal and Stateimplementation of RCRA. Today's rulealso requires fewer reports andmandatory Agency reviews than theproposal while still providingopportunity for Agency reviews.

IV. Detailed Discussion of the Final Rule

A. Scope of the Rule

The double liner and leak detectionstandards in today's final rule apply tonew and replacement landfills, surfaceimpoundments, and waste piles, andlateral expansions of these units.Today's rule applies, as it was proposedin May, 1987, to these units regardless oftheir permit status, including facilitiesthat were issued permits prior to andafter the enactment of HSWA andfacilities that are still in interim status.In consideration of the explicit languageof section 3004(o)(4) defining a new unitas a unit for which constructioncommences after the promulgation dateof today's rule, the Agency maintainsthat the permit does not act as a shieldwith respect to the leak detectionrequirements under today's rule for newunits. Because lateral expansioris andreplacement units are comparable intheir environmental impact, the Agencyhas, as a policy matter, decided tosimilarly remove the permit as a shieldfor leak detection systems atreplacement units and lateralexpansions of existing units. EPAbelieves that the opportunity forconstructing replacement units andlateral expansions of existing units tomeet today's requirements is similar tothat for new units. In addition, byrequiring replacement units and lateralexpansions at existing units to meettoday's requirements, EPA is ensuringthat these units meet the same minimumtechnological requirements and providethe same protection of human healthand the environment. Therefore, theAgency is amending § 270.4 to require




owners or operators to apply for apermit modification to meet thestandards of today's final rule. Ownersand operators at permitted facilities maynot begin construction of units subject totoday's requirements, until thepermitting Agency has approved theowner or operator's permit modification(see § 270.42).

Today's rule exempts certainreplacements of permitted surfaceimpoundment, waste pile, and landfillunits from today's double-liner and leakdetection system requirements.However, EPA has modified the scopeof the exemption since the May 29, 1987proposal. Sections 264.221(f), 264.251(f),264.301(f), 265.221(c), 265.254(a), and265.301(c) in today's rule exemptreplacements of surface impoundments,waste piles, and landfills from thedouble-liner system and leak detectionrequirements if the replacements meetthe following conditions: (1) The existingunit was constructed in compliance withthe design standards for double-linerand leachate collection systems insections 3004 (o){1)(A(i) and (o](5) ofRCRA; and (2) there is no reason tobelieve that the liner system is notfunctioning as designed. Of course, anyreplacement surface impoundment,waste pile, or landfill unit that otherwisequalified for a variance from the double-liner and leachate collection systemrequirements pursuant to sections3004(o)(2), 3004(o)(3), or 3005(j) of RCRAremains exempt from today's double-liner and leak detection requirements.

In the May 29, 1987 proposed rule,EPA considered exemptingreplacements that were constructed incompliance with existing part 264 single-liner requirements for surfaceimpoundments, waste piles, andlandfills. EPA acknowledges that thearguments for this exemption in theproposed rule were erroneous and hasdecided not to exempt replacements ofpermitted single-lined surfaceimpoundments, waste piles, andlandfills in today's final rule, becauseowners or operators of these units haveno early method of detecting whetherthe single liner is leaking. Owners oroperators of such units would have torely on ground-water monitoring todetermine if the single liner was leaking.EPA agrees with the commenters thatthis is inconsistent with the statutorygoal of leak detection at the earliestpracticable time and of preventingleakage out of the unit.

The May 29, 1987 proposal indicatedan effective date for most of theprovisions, including the leak detectionrequirements, of six months afterpromulgation. The July 29, 1992 effective

date of today's rule is consistent withthat proposal and with section 3010(b) ofRCRA. It is important to note thatsection 3004(o)(4)(B)(ii) defines "newunits" as those units on whichconstruction commences after date ofpromulgation (versus the effective date)of the Agency's rule for leak detectionsystems. Therefore, due to the clearlanguage of the statute, construction ofnew landfills, new surfaceimpoundments, and new waste piles isdefined with respect to the promulgationdate but today's final regulationsbecome effective 6 months afterpromulgation. This interpretation isconsistent with the Agency's definitionof "new tank systems" discussed in thefinal hazardous waste tankrequirements (51 FR 25446).

During the six month time periodbetween promulgation and the effectivedate, owners and operators of new unitshave time to determine and then makeany necessary adjustments to theirdesigns, contract specifications, andother pre-construction plans so that therequirements of today's rule aresatisfied by the effective date. This alsoallows adequate time, in the Agency'sopinion, for preparation and submissionto the Agency of documents andrequests for approvals that areprerequisites to construction andoperation. For permitted facilities, thisincludes permit modification requests.Similarly, any interim status facility thatadds a new unit following thepromulgation date is expected to complywith the requirements in today's rule tosubmit, along with their notificationunder § § 265.221(b), 265.254(a), or265.301(b), proposed action leakagerates and a response action plan, if thedue date for that notification (i.e., atleast 60 days prior to receipt of waste inthe new unit) falls before the effectivedate.

Thus, the Agency anticipates that atthe few facilities (both permitted andinterim status) that plan to develop newunits during this six month period, mostof the effort will be the preparatorydesign and administrative work neededto comply by the effective date. Ifowners or operators at interim statusfacilities should commence constructionof new units during this period, theconstruction would be subject to Agencyreview upon the effective date of today'srequirements.

Replacement landfills, surfaceimpoundment, or waste piles, or lateralexpansions to those units are, in theabsence of specific statutory direction,subject to this rule after July 29, 1992(i.e., six months after promulgation as

normally provided under section 3010(b)of RCRA).

It should be noted that EPA interpretsthe term "construction commences," asused in the "new unit" definition ofsection 3004(o)(4)(B)(ii) and in today'srule, according to its definition withinthe § 260.10 definitions of "existinghazardous waste management (HWM)facility" and "existing tank system."That is, a unit has commencedconstruction if (1) the owner or operatorhas obtained the Federal, State andlocal approvals or permits necessary tobegin physical construction, and either(2)(i) a continuous on-site, physicalconstruction program has begun; or (ii)the owner or operator has entered into acontractual obligation-which cannot becanceled or modified withoutsubstantial loss-for physicalconstruction of the facility to becompleted within a reasonable time.Therefore, any new unit that hascommenced construction, according tothis long-standing Agency definition ofthe term, prior to the promulgation date(i.e., today's Federal Register publicationdate) is outside the scope of today'srule. Similarly, any replacement unitthat is reused (unlike new units andlateral expansions, construction is not anecessary step prior to reuse of areplacement unit) or lateral expansionon which construction commences priorto the effective date (i.e., six monthsafter today's Federal Registerpublication date) of this rule is alsobeyond the scope of today's rule.

Today's rule includes a definition of"replacement unit" in § 260.10. EPA istoday defining a replacement unit as aunit (1) from which all or substantiallyall of the waste is removed, and (2) thatis subsequently reused after July 29,1992 to treat, store, or dispose ofhazardous waste. This definition, whichis similar to the May 29, 1987, proposalis consistent with the definition EPA hasused in implementing the statutory linerrequirements of section 3004(o)(5)(B) forreplacement units.

In the 1987 proposal, EPA excludedfrom the definition of replacement unitsthose units from which waste wasremoved and treated in preparation forclosure and only the treated waste wasreplaced in the unit. EPA explained inthe proposal that replacement units areunits that remain in service for activewaste management, not units that arepermanently taken out of servicethrough closure. EPA believed thisapproach not only reflected statutoryintent, but also would encourage (or atleast not discourage) environmentallybeneficial activities during closure (e.g.,waste treatment), because owners or

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operators would not have to retrofitclosing units from which waste wasremoved and replaced.

Today's definition of "replacementunit," like the proposal, exempts certainunits undergoing closure. However, theexemption is slightly expanded in thattoday's definition of replacement unitwould also exempt those closing unitsthat receive compatible wastes fromother closing units and/or correctiveaction areas at the facility, provided thatsuch use of the closing unit is approvedby EPA (or an authorized state) in thefacility's closure plan or correctiveaction program. The Agency believesthat the expanded exemption is a logicalextension of the proposal since it issimilarly necessary to encourageenvironmentally beneficial activities(e.g., treatment and consolidation ofcompatible wastes from on-site closingunits into one unit, waste removal toinspect a liner, expeditious closure ofother on-site units) that may nototherwise occur if the owner or operatorhad to retrofit the closing unit to meettoday's liner and leak detection systemrequirements.

Thus, units and activities qualifyingfor exemption from the "replacementunit" definition are limited to thefollowing conditions and safeguards: (1)The activity must be reviewed andapproved by EPA or an authorized stateas part of the closure plan or correctiveaction approval process, including acorrective action order; (2) only closingunits that have notified EPA inaccordance with § 264.113 or § 265.112or notified an authorized State, mayqualify: and (3) only compatible wasteand debris that are from closing units orcorrective action areas on-site may bedeposited in these units. For a unit toqualify for this exemption, off-sitewaste, new waste generated on site, andwaste from active units on site may notbe disposed of in the unit.

The situations EPA envisions asqualifying for this exemption from the"replacement unit" definition include:(1) Waste is removed from a closingunit, treated (e.g., incinerated,dewatered, or solidified), and returnedto the same unit: (2) waste is removedfrom a closing unit to inspect and/orrepair the liner, and the waste isreturned to the same unit; (3) scenario 1or 2, plus waste from other closing unitsis disposed in the original unit; and (4)scenario I or 2, plus waste that is theresult of corrective action at the samefacility, is placed into the original unit.

Finally, EPA also proposed in the May29, 1987, rule that the liner and leakdetection system requirements apply tosignificant unused portions of existingunits, where those portions did not have

double liners and leachate collectionsystems meeting the minimumtechnological requirements. Today's rulehas dropped this requirement. A numberof commenters on the proposal pointedout the difficulty of defining"significant" unused portions of a unit,and EPA was unable to develop anunambiguous definition. Furthermore,after reviewing land disposal unitsconstructed and permitted since 1984(which is the universe most likely tohave portions of units not yet coveredby wastes), EPA noted that virtually allof these units were required in theirpermits to incorporate double liner andleak detection requirements into theirrespective designs. Therefore, EPA hasconcluded that it is no longer necessaryto extend today's rule to significantunused portions of existing units. Itshould be noted, however, that lateralexpansions of existing units remainsubject to today's rule.

B. Standards for Liners and LeakDetection Systems

1. Technical Standards for LinerSystems

Today, EPA is promulgatingregulations containing design standardsfor double liners in accordance with therequirements of section 3004(o)(1) and(o)(5)(A) of RCRA. These standardsreplace those contained in the interimstatutory design provision of section3004(o)(5)(B) of RCRA that were codifiedon July 15, 1985 (50 FR 28702).

Today's rule amends the double-linerrequirements for surface impoundmentsand landfills in § § 264.221(c), 264.301(c),265.221(a), and 265.301(a). The majorchange from the existing rule is that thefinal rule requires owners or operatorsto install a composite bottom liner.Based on available data and publiccomments received by the Agency, thedouble liner system specified in today'srule, with the composite bottom liner,represents the best available technologywith respect to: (1) Preventinghazardous constituent migration out ofthe unit during the active life and post-closure care period, (2) detecting leaksthrough the top liner at the earliestpracticable time, and (3) maximizing theefficiency of the leachate collection andremoval system.

Today's rule does not change theexisting top liner performance standardfor surface impoundment and landfillunits. Owners or operators of affectedunits must still design the top liner toprevent the migration of hazardousconstituents into the liner throughout theactive life and post-closure period. EPAnotes that for purposes of today's rule,the top liner is the liner directly above

the leachate collection and removalsystem serving as the leak detectionsystem (see Technical Standard for LeakDetection Systems in Section IV.B.2 oftoday's preamble).

The Agency, in the preambles to theJuly 26, 1982 rule (47 FR 32274) and theMarch 28, 1986 proposal (51 FR 10709),endorsed geomembranes as meeting thetop liner performance standard. EPAwas aware of a number of landfill unitdesigns that included a composite topliner consisting of a geomembrane uppercomponent and a compacted soil or asoil/bentonite blanket lower component,Consequently. EPA raised severalquestions in the preamble to the May 29,1987 proposal concerning the use of acomposite liner as a top liner and theeffect the compacted soil componentwould have on other components of thedouble liner system, principally theearly detection of a leak through theupper geomembrane.

The Agency received severalcomments on this issue, all of whichwere in favor of allowing the use of acomposite liner as a top liner. Onecomment on appropriate standards for acomposite liner favored minimumthickness requirements for a compactedsoil lower component. Mostcommenters, however, favored norestrictions on the use of top compositeliners.

In response to these comments, EPA isnot prohibiting the use of composite topliners in today's rule. A parentheticalreference to geomembranes has beenincluded as an example to illustrate thatthe performance standard can be metthrough use of a ge'omembrane. EPAdoes not intend that this reference beinterpreted to mean that thegeomembrane is the only top linerdesign that will meet the performancestandard. EPA does not want todiscourage owners or operators fromusing top composite liners because suchliners can provide additionalenvironmental benefits by minimizingthe flow rate through a leak in ageomembrane liner and potentiallyminimizing migration of hazardousconstituents by attenuation. Althoughnot specified in today's rule, EPAmaintains that the soil component of thetop liner, however, should generally notbe more than three feet thick since athickness of 2 to 3 feet adequatelyserves the purpose of minimizing theflow through the geomembranecomponent (a lesser thickness may beappropriate for soil/bentonite blankets).EPA finds that this depth balances theincreased environmental protectionafforded by top composite liners and theability to detect leaks at the earliest




practicable time, The Agency does notintend, however, to imply that multipleliner systems (including multiplecomposite liners) or that thicker soilcomponents of bottom liners (e.g., 4 or 5feet) should be precluded.

EPA notes that such generalperformance standards provideflexibility which is essential since linerand leak detection system technologieshave advanced significahtly over thepast several years and are continuing todo so. Some examples include the use ofgeonets, the use of geotextile fabricfilters, and better seaming andconstruction quality assurance. RecentEPA studies show soil/bentoniteblankets may be effective and reliablecomplements to top liners, resulting in anew type of composite top liner. Astechnologies improve, today'sperformance standards will allowdifferent materials and designs to beused and specified in permits as site-specific considerations.

Today's rule amends the requirementsfor bottom liners at surfaceimpoundment and landfill units torequire owners and operators of unitssubject to today's rule to use acomposite bottom liner instead of acompacted-soil bottom liner allowed bythe interim statutory design. Thecomposite bottom liner required bytoday's rule specifies that the uppercomponent of the bottom-liner mustconsist of a geomembrane, and thelower component of the bottom-linermust consist of a minimum of 3 feet ofcompacted soil with a hydraulicconductivity of no more than I X10,

7

cm/sec. The compacted soil componentmust be able to minimize hazardousconstituent migration in the event of abreach in the geomembrane.

In the March 28, 1986 proposal, EPAoffered two options for the bottom linerof the double-liner system. One optioncorresponded to a compacted soil linerwith a maximum hydraulic conductivityof 1X10 .7 cm/sec and sufficientthickness (minimum 3 feet) to preventhazardous constituent migration throughthe liner during the active life and post-closure care period (51 FR 10710). Theother proposed option was thecomposite liner specified in today's rule,consisting of a top component thatwould prevent hazardous constituentmigration into the top component (ageomembrane) and a bottomcompacted-soil component with amaximum hydraulic conductivity ofIX10'7 cm/sec and the preamble to theproposal recommended a minimumthickness of 3 feet (90 cm).

EPA received comments supportingboth bottom liler options. Severalcommenters argued that the compacted

soil bottom liner, coupled with theleachate collection and removal systembetween the top and bottom liners,would provide adequate protection ofthe environment. Some of thesecommenters also proposed the use of acomposite top liner with a compactedsoil bottom liner. Others supported theuse of composite bottom liners as thedesign best able to enhance leachatedetection, collection, and removalefficiency of the leachate collection andremoval system between the liners.Several commenters favored thepromulgation of performance standardsin the rule and the specification ofdesigns and materials in accompanyingguidance documents.

After the proposal, EPA compiledinformation and data on performance ofthese two bottom liner systems withrespect to maximizing leachatedetection, collection, and removal, andpreventing hazardous constituentmigration out of the unit. The linerswere evaluated based on leachatecollection efficiency, leak detectioncapability, and leakage through thebottom liner. Results from computersimulations and engineering calculationsshowed that, on a comparative basis,the composite bottom liner will performsignificantly better than the compactedsoil liner with respect to the three 'criteria. The results were summarized inthe April 17, 1987 Notice of Availabilityof Information (52 FR 12566-12575), withmore detailed discussion of thecalculations and analytical approachcontained in the "Bottom Liner ,Performance in Double-Lined Landfillsand Surface Impoundments" (EPA/530-SW-87--013). In the May 29, 1987proposed rule on leak detection systems,the Agency indicated that it was likelyto finalize a rule on double liners thatwould require a composite bottom lineras the generally applicable standard (52FR 20251).

EPA also conducted a review ofapplications submitted for RCRAhazardous waste facility permitsbetween November 8, 1984 and February1987 to determine the type of bottomliner selected for installation at newlandfills and surface impoundments. Ofsome 183 units for which permitapplications were submitted as ofFebruary 1987, only seven units were tobe constructed with compacted soilbottom liners. The vast majority ofowners or operators selected thecomposite bottom liner rather than acompacted soil bottom-liner. Morerecent data available to EPA alsoconfirms that the majority of ownersand operators are using compositebottom-liners in their designs ofhazardous waste surface impoundment

and landfill units (Supporting Document#3 "Compilation of Current Practices ofLand Disposal Facilities," 1992).

In summary, today's rule requirescomposite bottom liners, based on: (1)Available information that compositebottom-liners perform significantlybetter than compacted soil liners interms of maximizing leachate detection,collection, and removal, and preventinghazardous constituent migration out ofthe unit; and (2) evaluation of currenthazardous waste industry practices.

Consistent with existing requirementsfor single liners at surfaceimpoundments and landfills, today's rulein §§ 264.221(c)(1)(ii), 264.301(c)(1)(ii),265.221(a), and 265.301(a) requires thateach liner that is included in the unit'sdesign must be chemically resistant tothe waste, placed on a structurallystable foundation, and large enough tocover all areas likely to be expdsed tothe waste.

Double liner systems must beconstructed of materials that haveappropriate chemical properties andsufficient strength and thickness toprevent failure due to pressure gradients(including status head and externalhydrogeologic forces), physical contactwith the waste or leachate to which theyare exposed, climatic conditions, thestress of installation, and the stress ofdaily operation. The liners must beplaced upon materials capable ofproviding support to the liners andresistance to pressure gradients aboveand below the liners to prevent failureof the liners due to settlement,compression, or uplift. They must alsobe installed to cover all surroundingearth likely to be in contact with thewaste or leachate.

2. Technical Standards for LeakDetection Systems

EPA is today establishing designstandards for the leak detection systemsfor new landfills, surface impoundments,and waste piles, and replacements andlateral expansions of these units(§§ 264.221(c)(2), 264.251(c)(3),264.301(c)(3), 265.221(a), 265.254(a), and265.301(a)). These leak detectionstandards are designed to detect a leakthrough the top liner at the earliest ofpracticable time. Today's final rule alsoestablishes the following design criteriafor leak detection system drainagelayers for affected landfills, surfaceimpoundments, and waste piles: (1) Aminimum bottom slope of 1 percent; (2) aminimum thickness of 1 foot and aminimum hydraulic conductivity ofI X10-2 cm/sec for granular materialsused for the drainage layer for wastepiles and landfills and X10 - 1cm/sec

3467



3468 Federal Register / VL 57, No. 19 / Wednesday, January 29, 1992 I Rules and Regulations

for granular materials used in surfaceimpoundments; (3) a minimum hydraulictransmissivity of 3 x10- 5 ms/sec forsynthetic materials used in drainagelayers for waste piles and landfills and3 X10-4 m 2/sec for synthetic drainagematerials used in surfaceimpoundments; and (4] sump design andoperating requirements.

Location of leak detection systems.EPA proposed in the May 29,1987preamble (52 FR 20229) that the leachatecollection and removal system adjacentto and below the top liner and above thebottom liner be designated as the leakdetection system, but requestedcomments on the proper location of theleak detection system in a system withmore than two liners. Commenters onthis aspect of the rule stated that theleak detection system should be locatedimmediately above the bottom liner.These comments claimed that specifyingadditional leachate collection andremoval systems above the bottom lineras leak detection systems would createa regulatory disincentive for owners andoperators to design systems with morethan two liners by requiring theseadditional (intermediate) leachatecollection and removal systems to meetthe requirements for leak detectionsystems and to implement responseactions in accordance with the unit'sresponse action plan. As a result ofthese comments, EPA is todayspecifying that the leak detection systemis the leachate collection and removalsystem drainage layer locatedimmediately above the bottomcomposite liner. Under today's final rule,any additional leachate collection andremoval systems located above the leakdetection system are not required tomeet the design and performancestandards for leak detection systems.

Leak detection time. The designstandards being promulgated today forleak detection systems will ensure thatthese systems meet the requirement insection 3004(o)(4) of RCRA for thedetection of leaks of hazardousconstituents at the "earliest practicabletime". EPA has interpreted the term"earliest practicable time" to be the timelapse from the time a liquid has passedthrough a breach in the top liner to thetime a technology-based leak detectionsystem can detect the liquid, assumingsaturated, steady-state flow. Withoutthese simplifying assumptions,modelling flow rates in the leakdetection system is difficult given thecomplexity and uncertainty of fluid flowunder unsaturated conditions. Aftercareful consideration of publiccomments on the proposal, EPA hasdecided not to specify 1 day (i.e., 24

hours) as the earliest practicable timefor the detection of a leak through thetop liner.

Commenters on the proposed 1-dayleak detection time requirement arguedthat it was unnecessary and overlyrestrictive. Another commenter statedthat the detection time could not beverified by field measurements. EPAagrees with the commenters that theproposed 1-day leak detection timerequirement is unnecessary given thatthe Agency is promulgating minimumdesign specifications for leak detectionsystems. In addition, the Agencyacknowledges that field measurement ofleak detection times is a problem. EPAhas determined that a leak detectionsystem meeting today's designrequirements will be capable ofdetecting leaks "at the earliestpracticable time" consistent with thestatutory mandate. Therefore, EPA issimplifying the rule by deleting the 1-day performance standard.

Leak detection sensitivity. EPA is alsonot finalizing the proposed leakdetection sensitivity value of 1 gallonper acre per day (gpad) that wasproposed. When developing a leakdetection sensitivity performancestandard for the May 29, 1987 proposedrule, EPA conducted comparativestudies between the performance ofcomposite bottom liners versuscompacted soil bottom liners(Background Document "Bottom LinerPerformance in Double-Lined Landfillsand Surface Impoundments", 1987).These studies showed that compositebottom liners have a much moresensitive leak detection capability thando compacted soil-only bottom liners.For example, a compacted soil liner witha hydraulic conductivity of 1 X 10- 1 cm/sec will allow some liquid migration intothe liner, as a result, a simple, one-dimensional theoretical model predictsthat a leak will not be detected until theflowrate through the top liner isapproximately 80 gpad. In contrast,simple, one-dimensional theoreticalmodels predict that the leak detectionsensitivities of landfills and surfaceimpoundments with composite bottomliners similar to those required intoday's rule range from 0.001 to 0.1 gpad.Because EPA is today stipulating the useof a composite bottom liner, the Agencyis confident that lower leak detectionsensitivities will be achieved for allunits affected by today's rule.Consequently, a separate requirementfor leak detection sensitivity is no longernecessary and EPA has dropped thisrequirement from the final rule.

Slope. EPA is today finalizing aminimum slope requirement for the leak

detection system. After furtherconsideration of the slope requirement,the Agency has determined that aminimum 1 percent slope will provideadequate drainage at land disposal unitsat which proper construction qualityassurance is used to minimizesettlement (§§ 264.221(c)(2)(i),264.251(c)(3)(i), 264.301(c)(3)(i),265.221(a), 265.254(a), and 265.301(a)).The purpose of the requirement is topromote good drainage in the leakdetection systems of units affected bytoday's rule. This slope requirementapplies to all planar components of theleak detection system.

In the May 29, 1987 proposed rule,EPA proposed a 2-percent minimumslope but requested comments onwhether the minimum bottom slopeshould be increased to a value between2 and 4 percent. One commenterpreferred that a 3-percent bottom slopebe used to account for settlement in thefinal slope value. However, mostcommenters argued that the minimumshould not be above 2 percent,expressing opposition to raising theminimum slope value above 2 percent.Many of these commenters pointed outthat other improvements included in theproposed rules, such as constructionquality assurance and an increasedtransmissivity value for syntheticdrainage materials, would obviate theneed for a slope greater than twopercent. One commenter argued thatslopes of less than 2 percent should beallowed for certain circumstancesprovided that the leak detection systemmeets other minimum design criteriaand performance goals and the owner oroperator can demonstrate that post-construction settlement/consolidationwill be minimized or eliminated. TheAgency agrees that with good CQA alesser slope can be adequate.

Based on these comments, EPAcarefully evaluated the minimum bottomslope requirement for today's rule. EPArecognizes that slope is one of severalfactors that will affect the performanceof the leak detection system. Forexample, the hydraulic conductivity ofmaterials used in the drainage system isimportant. In addition, the appropriateminimum slope required will alsodepend on the spacing of leachatecollection laterals in the leak detectionsystem: closer spacing will allow for aflatter slope. All of these design factorsshould be considered in selecting theappropriate slope for the system.

EPA agrees with commenters thattoday's rule sets in place improvementsthat affect the minimum slope that isneeded to construct an effective leakdetection system. First, the new




requirement to install a compositebottom liner provides a smoothimpermeable base on which to installthe leak detection system. Thedecreased permeability of the compositebottom liner over that of a soil linerrequired under previous regulationsallows for a reduced slope while at thesame time continuing to promote gooddrainage. Second, today's enhancedconstruction quality assurancerequirements enable owners oroperators the flexibility to build a flatterslope by maintaining consistentdrainage without significant ponding ofliquids. In addition, some of the new,rapidly draining synthetic drainingmaterials promote more rapid drainageon flatter slopes.

Because of these improvements, EPAbelieves that minimum bottom slopes ofless than 2 percent should be allowedwhere the owner or operator uses properconstruction quality assurance tominimize settlement and resultantponding of any leachate, as required by§§ 264.19 and 265.19 of today's rule.Such construction quality assuranceshould include surveying and otherinspection techniques to measure thehorizontal and vertical alignment of thebottom slope to minimize ponding andensure leachate flow to the sump. Someowners or operators may elect to designleak detection systems using bottomslopes of greater than 1 percent. EPAemphasizes that the requirementspromulgated today are minimumtechnical standards; owners andoperators can always adopt morestringent designs at their discretion.

Thickness of granular drainage layer.Today's rule also requires that agranular drainage layer be a minimum of12 inches in thickness for use in leakdetection systems of new andreplacement landfills, surfaceimpoundments, and waste piles, and forlateral expansions of these units(§§ 264.221(c)(2)(ii), 264.251(c)(3)(ii),264.301(c)(3)(ii), 265.221(a), 265.254(a),and 265.301(a)). EPA received nocomments on this requirement in theMay 29, 1987 proposed rule, andtherefore is finalizing the 12-inchthickness requirement as proposed. Thepurpose of this minimum thickness is todecrease the chance that the underlyinggeomembrane will be damaged byequipment during placement of thedrainage material. Current equipmentused to install granular layers can onlyplace drainage material to an accuracyof a few inches. The Agency isconcerned that if granular drainagelayers are designed to less than 12inches, this equipment could damage

underlying liners in areas where thedrainage material is thin.

Further, this requirement for granularlayer thickness is consistent withcurrent EPA policy. A 12-inch granularlayer thickness is specified in currentAgency guidance (BackgroundDocument "Draft Minimum TechnologyGuidance Document on Double LinerSystems", 1985). In addition, a recentEPA evaluation of existing hazardouswaste land disposal units (BackgroundDocument "Compilation of CurrentPractices at Land Disposal Units".January 1992) showed that 24 out of 28landfills, surface impoundments, andwaste piles with granular drainagelayers, had a specified thickness of 12inches.

Hydraulic conductivity of granulardrainage materials. EPA proposed torequire that granular materials used inleak detection systems have a minimumhydraulic conductivity of 1 cm/sec. TheAgency contended that greaterpermeability afforded by granularmaterials having 1 cm/sec hydraulicconductivity was necessary to minimizecapillary tensions present in leakdetection system granular materials andto satisfy the proposed leak detectiontime performance standard of 1 day.

EPA requested and receivedcomments on the proposed hydraulicconductivity requirement. Commentersopposed the 1 cm/sec requirement forseveral reasons. Several commentersstated that the requirement would forcethem to use rounded gravels or othergranular materials meeting the hydraulicconductivity value. These commentersmaintained that such materials wereeither not available or only available atsignificantly higher costs in many areasof the country. One commentersuggested that EPA should provide avariance to owners or operators in areaswhere suitable granular drainagematerials having the proposed hydraulicconductivity are unavailable. Anothercommenter stated that the Agencyshould continue to require granularmaterials to have minimum hydraulicconductivities of 1X10 - 2 cm/sec ascurrently specified in EPA guidance.This commenter asserted that sand,which is the most common granularmaterial used in leak detection systems,generally has a hydraulic conductivityof I x10- 2 cm/sec. Other commentersargued that using granular materialswith hydraulic conductivities on theorder of 1 cm/sec would significantlyincrease the susceptibility ofgeomembranes (above and below thedrainage layer) to puncture, because itwould be difficult to remove angularmaterials from the materials used to

construct the drainage layer. Anothercommenter argued that by requiringgranular materials to have a 1 cm/sechydraulic conductivity, EPA was forcingowners or operators to use syntheticdrainage materials that are incompatiblewith many materials used for syntheticliners.

The Agency acknowledges that theavailability of granular materialsmeeting the proposed hydraulicconductivity requirement may belimited. The Agency is also concernedwith the greater potential forgeomembranes to be damaged from theuse of granular materials havinghydraulic conductivities of I cm/sec. Inresponse to the commenters concerns,the final rule (§ § 264.221(c)(2)(ii),264.251(c)(3)(ii), 264.301(c)(3)(ii),265.221(a), 265.254(a), and 265.301(a))requires that granular materials used inleak detection systems at waste pile andlandfill units subject to today's rule havea minimum hydraulic conductivity of1× 10-2 cm/sec consistent with currentAgency guidance. However, the finalrule specifies that granular materialsused in leak detection systems atsurface impoundments subject totoday's rule must have a minimumhydraulic conductivity of I X 10- 1cm/sec.

The Agency has determined thatgranular materials used in leakdetection systems at surfaceimpoundments must have a higherhydraulic conductivity (one order ofmagnitude greater than what is currentlyspecified by Agency guidance) toaccount for the potentially greaterhydraulic heads imposed on the top linerin surface impoundments. Surfaceimpoundments are typically used tomanage liquids, therefore the hydraulicheads on the liner systems of these unitsare often much higher than those inwaste piles and landfills, which are notallowed to manage wastes containingfree liquids and must have a leachatecollection system above the top liner.Consequently, if a leak occurs in the topliner of a surface impoundment, and isnot rapidly drained to the detectionsump, areas of the bottom-liner systemwill potentially be subjected tohydraulic heads in excess of one foot,increasing the probability of migrationof hazardous constituents out of theunit. A greater permeability in the leakdetection system will drain any leakmore rapidly and thus reduce the headon the bottom liner system. Althoughgranular materials having hydraulicconductivities of I X 10-1 cm/sec willtypically be coarser sands and finegravels, the Agency feels that twocommon construction techniques can be

3469




used in combination to prevent anydamage to geomembranes adjacent tothe drainage materials. First, facilitiesmay select rounded drainage materials;these materials are less likely topuncture or otherwise damagegeomembranes. Second, owners oroperators may use additional layers ofsynthetic materials (e.g., a needle-punched nonwoven geotextile) next tothe liner to provide a cushion for thedrainage materials and reduce theprobability of puncturing. In addition,today's construction quality assurancerequirements help to assure against suchpunctures.

The Agency's recent evaluation ofcurrent industrial practices (see"Compilation of Current Practices atLand Disposal Facilities", January 1992)revealed that many facilities areselecting synthetic drainage materials,such as geonets, for their leak detectionsystems. Synthetic drainage materialsare often selected instead of granularmaterials because they typically requireless space and are easier to install thangranular materials. Also, as discussedbelow, virtually all synthetic drainagematerials have permeabilities greaterthan 10- 2 cm/sec.

Transmissivity of synthetic drainagematerials. EPA proposed a minimumtransmissivity value of 5 X 10-' m/secfor synthetic drainage materials that areused in lieu of granular drainagematerials. This value was selectedbecause it provides equivalent drainagecapacity to that of a granular drainagelayer meeting the requirements of theproposed rule; that is, 12 inches of agranular drainage layer with a hydraulicconductivity of 1 cm/sec. The minimumvalue of 5x10- m2/s for hydraulictransmissivity was based on numericalsimulations of typical leak detectionsystems. In these simulations, EPAconsidered a range of synthetic drainagematerials, including nets, mats, andwaffles. From the results of thesesimulations ("Liner and Leak DetectionRule Background Document", 1987), EPAconcluded that a hydraulictransmissivity value of 5 X 10-4 ma/secwould enable the leak detection systemto collect and remove relatively largeamounts of leakage while maintaininggravity flow conditions. This-specification was to ensure that theliquids in the leak detection systemwould be rapidly collected while thehydraulic head on the bottom linerwould be minimized.

One commenter objected to thetransmissivity standard, claiming that avalue of 5X10-'m'/sec is notachievable with a single layer ofcurrently available netting, and that

performance may be worse when creep,loading, and rib layover come intoeffect. EPA disagrees. The Agency hasdata (Liner and Leak Detection RuleBackground Document, 1987) showingtransmissivities of single layers ofsynthetic drainage materials producedby four major manufacturers under theconditions of ASTM Test Method D471-87 (that is, a pressure of 100kilopascals (kPa) and a hydraulicgradient between 0.1 and 0.25). At thetime of the proposal, thesetransmissivities ranged fromapproximately 2X10-4m2/sec to 4X10-1m2/sec. Improvements in geonets sincethen have resulted in typicaltransmissivities of 2 X10

-3 to 4 X10

-3

mi/sec using the same ASTM testmethod. The Agency maintains that theconditions at which ASTM D 471-87 isconducted are representative of thepressures and hydraulic gradients inmany land disposal units, and as aresult, a transmissivity value of 5 X10-4

mi/sec can be obtained with typicalcommercially available syntheticdrainage materials. However, theAgency recognizes that the requirementsfor synthetic drainage materials shouldbe consistent with the requirements forgranular drainage systems in leakdetection systems. Thus, the Agency hasrevised the transmissivity requirementsin today's rule (§I 264.221(c)(2)(ii),264.251(c)(3)(ii), 264.301(c)(3)(ii),265.221(a), 265.254(a), and 265.301(a)) torequire that synthetic drainage materialsachieve equivalent flow rates todrainage layers utilizing granularmaterials.

Other performance requirements.Today's final rule also includes severalgeneral performance standardrequirements for leak detection systemsthat are simply restatements of what isalready required in existing regulationsfor leachate collection and removalsystems at surface impoundments,waste piles, and landfills subject totoday's final rule. Under today's rule,leak detection systems for affected unitsmust be constructed of materials thatare chemically resistant to wastes andleachate in the unit, and be of sufficientstrength to resist pressure gradientsgenerated within the unit(§§ 264.221(c)(2)(iii), 264.251(c)(3)(iii),264.301(c)(3)(iii), 265.221(a), 265.254(a),and 265.301(a)). These requirements aredesigned to ensure that leak detectionsystems are not damaged from chemicaland physical stresses associated withthe unit. Also, these requirements aresimply an extension of the performancestandards for liners.

Leak detection systems for unitsregulated under today's rule must also

be designed and operated to minimizeclogging during the active life and post-closure period (§ § 264.221(c)(2)(iv),264.251(c)(3)(iv), 264.301(c)(3)(iv),265.221(a), 265.254(a), and 265.301(a)).This requirement is to ensure thatdrainage in leak detection systems is notimpeded over time. EPA is concernedabout the potential for drainage layersto become clogged as a result ofphysical, chemical, or biologicalmechanisms. EPA data indicate that thepotential for clogging increases as thehydraulic conductivity of drainagematerial decreases. Examples oftechniques to minimize clogging include:Using properly graded granular filtermaterials, filter fabrics (geotextiles), orother filter materials to reduce fines;using poorly graded (i.e., uniform)granular drainage material; increasingcollection pipe slot numbers or size:reducing liquid residence time byincreasing slope, decreasing pipespacing, or increasing the size ofgranular drainage material; and cleaningcollection system pipes and drainagemedia using hydraulic jetting, steam, oracidic solutions.

In addition, today's rule requires thatleachate collection and removal systemsimmediately above the top liner (forlandfill and waste pile units) be capableof ensuring that the leachate depth overthe top liner does not exceed 1 foot (30cm) as proposed in the March 28,1986proposed rule. EPA received nocomments on these requirements and istherefore finalizing them as proposed.

EPA is today also promulgatingseveral requirements for sumps that arepart of a leak detection system. Ownersor operators of new and replacementlandfills, surface impoundments, wastepiles. and lateral expansions of suchunits must use sumps of sufficient size tocollect and remove liquids efficientlyand prevent these liquids fromaccumulating on the drainage layer. Inaddition, the design of the sump andremoval system must provide a methodfor measuring and recording the volumeof liquids present in the sump and ofliquids removed. EPA received nocomments on these requirements and istherefore finalizing them as proposed(§§ 264.221(c)(2)(v), 264.251(c}{3)(v),264.301(c)(3)(v), 265.221(a), 265.254(a),and 265.301(a)).

EPA is today promulgating arequirement for owners or operators ofunits affected by today's rule to collectand remove pumpable liquids in leakdetection sumps to minimize the headon the bottom liner {§ 264.221(c)(3),264.251(c)(4), 264.301(c)(4), 265.221(a),265.254(a), and 265.301(a)). The Agencyhad proposed, in the May 29, "1987




Federal Register, that the head in thesump for the leak detection sump beminimized; in the preamble, the Agencysuggested that the average liquid levelsin the sump should be below 12 inches.One commenter on the proposed rulestated that the 12-inch maximum wasunachievable in many instancesbecause of the size and geometry ofmost sumps and the pumps used toempty them. The commenter alsomentioned that automated level controlsystems and minimum submergencerequirements make the 12-inchmaximum level an impossibleperformance standard. EPA agrees thatthe geometry of sumps may vary andthat minimum pumping levels may begreater than 1 foot. Thus, the Agency isnot setting a maximum level of liquids inthe sump, but specifying only that thehead on the bottom liner must beminimized by requiring owners andoperators to remove pumpable liquidsfrom the sump. "Pumpable liquids"means any amount of liquids that can bereasonably pumped out of the sump,based on sump dimensions, pumpoperating levels for automated pumpsystems, and the goals of minimizinghead in the sump and backup of liquids(from the sump and drainage tile orpipes) into the drainage layer.

Today's rule also modifies thedefinition of the term "sump" in § 260.10to redefine sumps used as part of leakdetection systems for waste piles,surface impoundments, and landfills.The purpose of this modification is tomake clear that the regulations forhazardous waste tanks that areotherwise applicable to certain sumpsdo not apply to those sumps used atland disposal units that function as partof the leak detection system. Thesesumps serve fundamentally differentpurposes than many other types ofsumps. Sumps used at land disposalunits are usually surrounded by one ormore liners; therefore, manyrequirements, especially secondarycontainment, are not practicable forthese units. The Agency maintains thatsubjecting these units to therequirements for hazardous waste tankswill not provide a substantialenvironmental benefit and has thereforemodified the definition of the term sumpto redefine sumps used as part ofleachate collection and removal or leakdetection systems for surfaceimpoundments, waste piles, andlandfills.

Finally, today's rule includes arequirement applicable only to thoseleak detection systems installed at new,replacement, or lateral expansions oflandfiPs surface impoundments, and

waste piles that are not located abovethe seasonal high water table. EPAreceived no comments on thisrequirement and is finalizing it asproposed. The Agency is thereforerequiring in today's rule that owners oroperators of leak detection systems notlocated completely above the seasonalhigh water table demonstrate that theoperation of the leak detection systemwill not be adversely affected by thepresence of ground water(§ § 264.221(c)(4), 264.251(c)(5),264.301(c)(5), 265.221(a), 265.254(a), and265.301(a)).

3. Alternative SystemsAlternative designs. The existing rules

(§ § 264.221(d), 204.251(b), 264.301(d),265.221(c), and 265.301(c)) alreadyprovide for alternative designs to theliners and leachate collection andremoval systems if an owner or operatorcan demonstrate that an alternativedesign will prevent the migration of anyhazardous constituent into the groundwater or surface water at least aseffectively as the requirements in§§ 264.221(c), 264.251(a), and 254.301(c),as appropriate. Today's rule adds§ § 264.221(d), 264.251(d), 264.301(d),265.221(a), 265.254(a), 261.301(a) to allowalternative designs for leak detectionsystems that are capable of detectingleaks of hazardous constituents at leastas effectively as the new leak detectionsystem requirements in § § 264.221(c)(2),264.251(c)(3), 264.301(c)(3), 265.221(a),265.254(a), and 265.301(a). EPA feels thatvariance procedures allow owners oroperators flexibility in designing theirleak detection systems withoutdiscouraging the use of new leakdetection systems.

In order to be granted a variance fromthe leak detection requirements oftoday's final rule, an owner or operatormust demonstrate to the RegionalAdministrator that the proposed designdetects leaks through the top liner atleast as effectively as a leak detectionsystem designed to meet today'sminimum design standards. In decidingwhether to allow a variance for analternative leak detection system ortechnology, the Regional Administratorwill consider. (1) The ability of theproposed system or technology tooperate as effectively through the activelife and post-closure period of the unitas a unit designed using the minimumdesign specifications; (2) the nature andquantity of the wastes to be managed inthe unit; and (3) the ability of the systemto detect leaks, and in combination withresponse actions to be taken upondiscovery of leakage, prevent migrationof hazardous constituents out of the unitduring the active life and post-closure

care period. For example, an alternativeleak detection system that did notprovide information about leakage untilafter the leakage migrated through thebottom liner would be deemedunacceptable, because such a systemwould trigger an owner or operatorresponse after hazardous constituentsmigrated into the environment.

Owners or operators may apply for aVariance if they wish to propose a leakdetection system design that deviatesfrom today's design parameters. Forexample, if an owner or operatorspecified that the drainage layer of asurface impoundment would utilizegranular materials having a hydraulicconductivity of 1 X10-2 cm/sec (insteadof the minimum required value ofIX10- 1cm/sec), the owner or operatorwould have to describe how othercomponents of the system (e.g., depth ofimpoundment, bottom slope, flow pathto a collection pipe or sump or pipespacing) or the action leakage rate orresponse action plan would detect leaksat the earliest practicable time, minimizehead on the bottom liner, and preventmigration of potentially hazardousconstituents out of the unit as effectivelyas the design required in today's rule.

Temporary units. In the May 29, 1987proposal EPA invited comment aboutwhether double liners and leachatecollection systems are necessary for allwaste piles, or if alternative systemsmight provide adequate environmentalprotection at some units. In response tothe Agency's request, a commenterquestioned whether double liner andleachate collection systems arenecessary for short-term waste pilescreated during corrective action. Thesame commenter also suggested thatEPA should propose an overall policy inits upcoming corrective action rule as towhat technological requirements willapply to units used for corrective action.

The Agency agrees with thesecomments. There are circumstanceswhere the Agency believes it shouldallow temporary units constructed as apart of corrective action pursuant to apermit or 3008(h) enforcement order, oran approved closure plan, to beconstructed without a double liner and aleachate collection system. Due to thelimited time these units are in operation,in concert with alternative design,location and operating practices, thereare situations which are equallyeffective as double lined units inpreventing migration of constituents toground water or surface water. Manywaste piles (as well as some temporarystorage surface impoundments) maythus qualify for the double liner waiver

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found in § § 264.221(d), 264.251(d),265.221(a), and 265.254(a).

These provisions provide for a genericwaiver of the double liner system, butdo not specifically address temporaryunits. In response to the special needsposed by corrective action and facilityclosure (e.g., rapid cleanup and short-term operation) the Agency haspublished a proposed "Subpart S" rule(55 FR 30798) that, among other things,specifically addresses standards fortemporary units. That proposal outlinesAgency guidance on what factors toconsider in determining what constitutesa temporary unit.

4. Applicability to Waste PilesEPA is requiring that new and

replacement waste piles, and lateralexpansions of waste piles, install,operate, and maintain double liner andleak detection systems (§§ 264.251 and265.254). The Agency is extending thedouble liner and leachate collection andremoval system requirements to wastepiles, as discussed in the preamble tothe May 29, 1987 proposal (52 FR 20250],because the Agency maintains, forseveral reasons, that these units posethreats similar to or greater thanlandfills concerning leakage through thetop liner and releases of hazardousconstituents. First, waste piles are oftenexposed to precipitation for longerperiods of time than landfills. Manyowners or operators of landfills providean intermediate cover to minimizeleachate generation; this practice is notas common for waste piles. Second,waste piles have a higher potential forequipment-related damage than dolandfills, because equipment isfrequently used to add and removewaste from piles during these units'active lives. This increased equipmentactivity at waste piles increases the riskof damage to the primary liner andmerits use of a secondary liner for theseunits. Finally, waste piles typically havemuch longer active lives than landfills:Waste piles are typically used for 20years or more, whereas landfill units aremore common used for periods of 6months to 5 years before being closed.

Today's rule provides a waiver fromthe double liner and leachate collectionand removal system requirements forcertain waste piles that are monofills. Inthe May 29, 1987 proposal rule, EPAproposed a variance for monofills when(1) the monofill contains only hazardouswastes from foundry furnace emissioncontrols or metal casting molding sand,(2) such waste do not containconstituents which would render thewastes hazardous for reasons other thanEP toxicity characteristic, (3) themonofill has at least one liner for which

there is no evidence that such liner isleaking, (4) the monofill is located morethan a quarter mile from an undergroundsource of drinking water, and (5) themonofill is in compliance with generallyapplicable ground-water monitoringrequirements for facilities with permits.The Agency proposed this waiver tocodify the language in section 3004(o)(3]of RCRA and to be consistent withregulations for landfills and surfaceimpoundments. Because EPA receivedno comments on this proposed waiver, itis being finalized as proposed in today'srule (§ § 264.251(e)(1) and 265.254(a)).

Today's rules do not affect theexisting exemption in § 264.250(c) andnow in § 265.254 for certain indoorwaste piles. These units continue to beexcluded from today's double-liner andleak detection requirements becausethey contain no free liquids and areprotected from precipitation and surfacewater run-on and are therefore unlikelyto have any leakage.

5. Applicability to Land Treatment UnitsEPA proposed a number of leak

detection requirements for landtreatment units in the May 29, 1987proposed rule. These requirementsincluded (1) a 95-percent confidencelevel for detecting hazardousconstituents in the treatment zone, (2)monitoring conducted above the'seasonal high water table, (3) responseaction plans, and (4) inspection ofunsaturated zone monitoring equipment.Today's rule does not include additionalleak detection requirements for landtreatment units. EPA has concluded thatthe current regulatory requirements forunsaturated zone monitoring at landtreatment units are sufficient to ensurethat leakage of hazardous constituentswill be detected at the earliestpracticable time. Therefore, EPA findsthat additional regulations for such unitsare not needed to meet the statutoryrequirements of section 3004(o)(4) ofRCRA for these units.

In the preamble to the 1987 proposal,EPA noted that unsaturated zonemonitoring systems serve as effectiveleak detection systems for landtreatment units. The Agency received nocomments challenging this position orsuggesting more effective alternatives.The existing regulations, however,already require unsaturated zonemonitoring-i.e., leak detectionsystems-at all land treatment units,both new and existing. Specifically,§ 264.278 and 265.278 contain detailed

technical standards for soil and soil-pore liquid monitoring in theunsaturated zone below the landtreatment unit to ensure detection of anyhazardous constituents migrating out of

the treatment zone. Furthermore, whenreleases are detected, the owner oroperator of a permitted facility isrequired to modify operating proceduresat the land treatment unit to preventfurther release. EPA has implementedthese requirements through twoguidance documents: "Permit GuidanceManual on Hazardous Waste LandTreatment Demonstrations" and"Guidance Manual on Unsaturated ZoneMonitoring for Hazardous Waste LandTreatment Units." After reviewingpublic comments and its experience inpermitting land treatment units since theproposal, EPA concluded that thecurrent regulatory requirements, coupledwith existing guidance, are sufficient toensure that leak detection systems innew land treatment units are capable ofdetecting releases at the earliestpracticable time.

In the May, 1987 proposal, EPA didnot propose to change the basicregulatory requirements for unsaturatedzone monitoring, but added severalrelatively minor amendments. Forexample, the proposal would haveadded a requirement that constituentsmigrating out of the treatment zone bedetected at a 95% confidence level andthat the unsaturated zone monitoringtake place above the seasonal highwater table as well as below thetreatment zone (as the current standardsspecify). EPA has concluded that theseminor changes are unnecessary, eitherto meet the statutory standard or toprotect human health and theenvironment. Available guidancedocuments already specify a 95% levelof confidence for monitoring, and EPAand the States have successfullyincorporated this standard into permits.Therefore, it is unnecessary to imposethis requirement as a matter ofregulation. Similarly, monitoring belowthe seasonal high water table is alreadyprohibited by the existing regulations.because monitoring below the watertable would not qualify as unsaturatedzone monitoring. Therefore, theregulatory requirement that themonitoring be above the seasonal highwater table is also unnecessary.

Today's final rule also does notfinalize requirements for a responseaction plan describing remedial action ifreleases are detected in the unsaturatedzone. EPA has concluded that aresponse action plan for permitted landtreatment units is superfluous, becausethe current regulations (§ 264.278(g))already require facility owners oroperators to take specific responses inthe case of hazardous constituentsdetected in the unsaturated zonemonitoring system. EPA also notes that



Federal Register / Vol. 57, No. 19 / Wednesday, January 29, 1992 / Rules and Reguiati4g

migration found in the unsaturated zonemonitoring system would constitutemigration from the unit and thereforecould be addressed by the Agency, ifnecessary, under RCRA correctiveaction requirements. Finally, EPA notesthat, because of the RCRA land disposalrestrictions, most If not all hazardouswaste land treatment units in the futurewill be able to operate only if wastesplaced in them meet applicabletreatment standards before placement inthe unit or if they are granted a no-migration variance. A unit granted a no-migration variance that then releaseshazardous constituents from the unitwould have to cease receipt ofprohibited wastes (§ 268.6(f)]. In thiscase, a unit found to be releasinghazardous constituents to theunsaturated zone would be required tocease operating. For these reasons, EPAhas concluded that a response actionplan is not necessary for land treatmentunits.

A December 6, 1991 decision of theUnited States Court of Appeals, Districtof Columbia addressed the soil-porewater monitoring requirements forInterim status land treatment facilities(She]] Oil Company v. EPA, No. 80-1532). As of the date of this rule, theCourt's mandate was not yet issued andthe regulation remains in place. TheAgency is still considering whatresponse to take to the Court's decision.

C. Response to Leaks

1. Action Leakage RateThe final rule requires owners or

operators to establish one actionleakage rate (ALR) for each unit affectedby today's rule (§ § 264.222, 264.252,264.302, 265.222, 265.225, and 265.302).The action leakage rate is a leakage ratethat requires implementation of aresponse action to prevent hazardousconstituent migration out of the unit.The Agency has determined, the publiccomments support, the need for an ALRand response actions that the ALRtriggers. EPA believes that the ultimategoal of the liner and leak detectionsystem requirements is to prevent therelease of hazardous constituents fromthe unit, thereby protecting the groundwater and sw'fAce water. A system inplace to detect leaks at the earliestpractical time should be complementedby early follow-up actions to effectivelyminimize the chance for migration ofhazardous constituents from the unit.Furthermore, it is often more effective toaddress leaks within the liners than tolater address ground-watercontamination through corrective action.

Today's final rule requires owners oroperators to monitor the rate of leakage

into the leak detection sump and todetermine whether the measured rate ofleakage over a specified period of timeexceeds the action leakage rate (see -Section IV.D. of the preamble for furtherdiscussion of today's monitoringrequirements). If the owner or operatordetermines that the measured rate ofleakage exceeds the ALR, the owner oroperator must notify EPA andimplement procedures contained in aresponse action plan that owners oroperators must prepare for unitsaffected by today's rule.

The proposed rule allowed the owneror operator a choice in establishing anaction leakage rate. EPA proposed tospecify an action leakage rate between5-20 gallons/acre/day (gpad).Alternatively, the owner or operatorcould propose a site-specific actionleakage rate for EPA approval. Theproposed rule required owners andoperators to develop and submit a planfor responding to the action leakagerate.

The proposed rule also requiredowners and operators to establish avalue and a response action plan for arapid and large leakage rate (RLL). TheRLL was defined as the maximumdesign leakage rate (plus a safety factor]that the leak detection system canremove under gravity flow conditions(i.e., without the fluid head on thebottom liner exceeding one foot ingranular leak detection systems andwithout the fluid head exceeding thethickness of synthetic lead detectionsystems). EPA also considered in theproposal the possibility of owners oroperators developing responses toleakage rates between the actionleakage rate and rapid and extremelylarge leakage rate (referred to as anintermediate leakage rate]. In addition,the Agency considered requiring ownersor operators to develop responses to"significant changes" in the flow rate(EPA suggested a 100 gpad or 25-50percent increase, whichever was larger.leakage that exceeded health-basedconcentrations of hazardousconstituents, and a leakage rateexceeding 50 gpad for any one-dayperiod. In summary, EPA discussed sixleakage rates in the proposal that couldtrigger various response actions byowners or operators.

Although no commenters objected tothe establishment of an action leakagerate. EPA received many comments onthe proposed action leakage rate value.Several commenters favored EPAsetting an action leakage rate within theproposed range of 5-20 gpad. Somesuggested that EPA should not finalize aspecific value within the proposed

range, but keep the range of 5-20 gpedand allow the permit writer to select aspecific value within the range to applyto the unit. Some commenters suggestedan action leakage rate of 50 or 100 gpad.Another commenter suggested that EPAset an action leakage rate at 75 percentof the proposed rapid and extremelylarge leakage rate. One commenterstated that the action leakage rateshould be decreased over the life of theunit according to a formula, thusallowing a higher action leakage rateduring initial operation of the unit toaccount for presence of liquids in thesump from sources other than leaks (e.g.,construction water).

In general, most commenters statedthat EPA had little or no field data to setan action leakage rate within theproposed range, and argued that theAgency should allow site-specific actionleakage rates to be set by the permitwriter, especially to account for otherpotential sources of liquids in the leakdetection sump (e.g., soil linerconstruction water, precipitation duringconstruction, and ground-waterinfiltration). Although the proposed rulewould allow site-specific variances tothe proposed action leakage rate,commenters expressed concern thatEPA would not allow many site-specificaction leakage rates. 'These commentersclaimed that site-specific action leakagerates based on the design and operationof the unit should be common.

EPA also received many comments onother leakage rates that would requireowners or operators to develop responseactions. Commenters opposed using"significant changes" in the flow rate orhealth-based concentrations ofhazardous constituents in liquidsentering the detection sump to trigger aresponse by the owner or operator.Commenters felt that the proposed"significant change" concept wasunclear and difficult to define.Commenters felt using leachate qualityanalysis at flow rates below the rapidand extremely large leakage rate totrigger a response was costly, time-consuming, and provided no additionalenvironmental benefit. Thesecommenters generally felt that liquidflow rates into the detection sumpshould be the sole trigger of an owner oroperator's response. Many of thesecommenters also disagreed with the useof health-based levels (e.g., maximumcontaminant levels) in the leachate totrigger a response. They argued thatEPA's assumptions in proposing suchlevels were overly conservative andunrealistic because such liquid was stillcontained in the leak detection systemand migration to the environment was

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controlled by the bottom-liner anddrainage system.

Many commenters maintained thatEPA was proposing too many leakagerates without a clear distinctionbetween them as to the differences inresponse associated with the leakage.These commenters claimed that some ofthe responses actions discussed by EPAin the preamble seemed to be redundantfor different leakage rates, and thatEPA's requirements were confusing,burdensome, and provided no additionalbenefit. As an example, the commenterscited that flow rates above the proposedaction leakage rate (5-20 gpad) wouldtrigger many of the same responses thatexceedance of other leakage rates, suchas the rapid and extremely large leakagerate (an example in the preambleshowed a RLL of 3000 gpad) orsignificant change in leakage rate,would mandate. Some of thesecommenters stated that leakage ratesless than the rapid and extremely largerate did not necessarily indicate afailure of the top liner, and that leakagewould still be contained within the unitby the bottom liner. Therefore, they feltthat the Agency should not stipulateexcessive and redundant responses onthe part of owners or operators forleakage rates that do not poseenvironmental concerns.

EPA requested and received field dataon actual leakage rates fromcommenters on the proposed rule, andobtained additional data from morerecent studies of leakage rates throughtop liners at land disposal units.However, these data are limited andfurthermore, indicate that a portion ofunits (>25%) with CQA could exceed 20gpad, the highest end of the proposedrange for action leakage rates.Therefore, the Agency agrees withcommenters that existing field data donot support establishment of an actionleakage rate within the proposed rangeof 5-20 gpad for all units.

In response to EPA's request forcomments on the appropriateness of theproposed range for surfaceimpoundments, commenters argued thatit was inappropriate for the Agency toset the same action leakage rate forlandfills and surface impoundments andthat the Agency should take intoaccount the type, size, and operation ofthe unit when establishing an actionleakage rate. EPA agrees with thecommenters that the size, type, andoperation of the unit should beaccounted for in establishing a leakagerate that will trigger a response by theowner or operator, and that a standardleakage rate value for all units is notappropriate at this time.

In addition, EPA acknowledgescommenters' concerns about theproposed number of leakage ratestriggering a response by the owner oroperator, and the lack of distinctionamong them for purposes ofimplementation. To simplify the finalrule, EPA has chosen to establish oneleakage rate that will trigger a responseby the owner or operator, account forthe site-specific design of the unit, andindicate significant evidence that thereis problematic leakage through the topliner that mandates a response. EPA isrequiring owners or operators topropose an action leakage rate for eachunit subject to today's rule based on anapproach that is similar to the proposeddefinition of the rapid and extremelylarge leakage rate. That is, owners oroperators must calculate an actionleakage rate based on the maximumdesign leakage rate that the leakdetection system can remove withoutthe fluid head on the bottom linerexceeding one foot. This leakage ratemust account for an adequate margin ofsafety for uncertainties in design,construction, and operation of the leakdetection system. The action-leakagerate must not be greater than the flowcapacity of the drainage layer in orderto assure detection of leaks (e.g., if theALR is 500 gpad and the flow capacity is400 gpad then the ALR would never beexceeded no matter how large the leak).The action leakage rate should alwaysbe less than or equal to the pumpingcapacity of the leak detection sumpsince the pumping capacity is requiredto be greater than the maximum leakdetection system flow rate under whichgravity flow conditions prevail (i.e., toprevent liquids from backing up into thedrainage layer). If the owner or operatordetermines that the action leakage rateis exceeded, the owner or operator mustimplement the procedures contained inthe response action plan.

EPA believes that flow rates in excessof the action leakage rate indicate amajor localized or general failure of thetop liner, thus increasing the potentialfor a buildup of head on the bottom linerand increasing the potential formigration of hazardous constituents intothe bottom liner. For this reason, it isnecessary to maintain leak detectionflow rates below the action leakage rateand for the owner or operator to takeresponse actions for leaks greater thanthe action leakage rate.

Under today's rule, as in the May 29,1987 proposal, the owner or operatormust propose an action leakage ratebased on calculations of the maximumflow capacity of the leak detectionsystem design so as not to exceed one

foot head on the bottom liner (calledrapid and extremely large leak in theproposal). The proposal backgrounddocument "Liner and Leak DetectionRule Background Document", (EPA/530-SW-87-015, May 1987) presented anumber of mathematical models formaking such a determination. All ofthese models are based on Darcy's Lawfor non-turbulent flow through saturatedmedia. Of these models, the Agencyfinds that the following formula for floworiginating through a hole in the liner isthe most likely leak scenario for ageomembrane liner:

Q=k.h.tan a.B

whereQ=flow rate in the leak detection system

(drainage layer),h=head on the bottom liner,k=hydraulic conductivity of the drainage

medium,a =slope of the leak detection system,B=width of the flow in the leak detection

system, perpendicular to the flow.

Using this formula, the Agencycalculated the maximum flow ratesusing the minimum specifications intoday's rule: 1% slope, and I X10 - 1 cm/sec hydraulic conductivity for surfaceimpoundments and 1× 10-2 cm/sechydraulic conductivity for landfills andwaste piles. Assuming that the head is 1foot and the width of flow (B) is 100 feet,the results show maximum flow rates of2,100 gpad for surface impoundmentsand 210 gpad for landfills and wastepiles. Using a safety factor of two, assuggested in the proposed rulepreamble, yields about 1,000 gpad forsurface impoundments and 100 gpad forlandfills and waste piles as the Agencyrecommended action leakage rates.Because this calculation used theminimum technical requirements andother design assumptions to maximizepotential head on the bottom liner, theAgency believes that the units meetingthe minimum technical requirementswould not require action leakage ratesbelow 100 gpad for landfills and wastepiles and 1000 gpad for surfaceimpoundments. The final backgrounddocument on action leakage rates("Action Leakage Rates for LeakDetection Systems," January 1992)provides further discussion andbackground on these recommendedaction leakage rates. As discussedearlier in the preamble, this document isavailable from the docket for this rule orfrom NTIS, U.S. Department ofCommerce.

While EPA recommends the aboveaction leakage rates for the minimumdesign specifications, the Agencyrecognizes that a number of site-specific




factors affect the maximum flowcapacity of a leak detection system, andowners or operators may want topropose alternative action leakage rates.For example, the leak detection systemdesign may be different than theminimums specified in today's rule. Asindicated above and in the backgrounddocument, hydraulic conductivity is afactor that significantly affects the flowcapacity of the system. The Agencybelieves that leak detection systemswith greater hydraulic conductivitieswould have higher action leakage rates.In additional, owners or operators mayhave information to justify a differentwidth of flow in the above calculation.Owners or operators also may justify ahigher action leakage rate by using adifferent formula or model. While theAgency recommends the use of theabove model for defining the maximumflow capacity of the leak detectionsystem and action leakage rate, EPArecognizes that there may be alternativemodels available now or in the futurethat may more accurately predict systemflow capacity to justify higher actionleakage rates. Therefore, owners oroperators may propose to use analternative model that they believe moreaccurately predicts the maximum flowcapacity of the leak detection system.Further, owners or operators may wantto do a flow (pump) test on the leakdetection system to show actual flowcapacity, which may justify a higheraction leakage rate. Finally, the owneror operator may have flow rate data onsimilarly designed units to use to justifya different level. As more and moreunits are built, the Agency as well asowners or operators will develop abetter data base that may be used toestablish appropriate action leakagerates.

For facilities seeking a permit, theaction leakage rate will be set after theRegional Administrator reviews the rateproposed by the owner or operator ineither the facility's part B permitapplication or permit modification. forinterim status facilities, the owner oroperator must submit a proposed actionleakage rate for the affected unit to theRegional Administrator 60 days prior tothe receipt of waste in the unit. TheRegional Administrator will eitherapprove, modify, or deny the proposedleakage rate. The RegionalAdministrator may extend the reviewperiod to evaluate the owner oroperator's proposed action leakage ratefor up to 30 more days. If none of theseactions occur within 60 days (or if thereview period is extended, within 90lays), the proposed rate can beconsidered approved.

Owners and operators of unitsaffected by today's rule must monitorthe leak detection sump and use themonitoring information to determine ifthe action leakage rate has beenexceeded. The final rule sets forth theprocedures owners or operators mustuse in determining whether the actionleakage rate has been exceeded§ § 264.222(b), 264.252(b), 264.302(b),265.222(c), 265.255(c), and 265.302(c)). Tocalculate the flow rate into the leakdetection sump, owners, or operatorsmust convert flow rate data into anaverage daily flow rate per acre (i.e.,gpad) for each leak detection sump. Thiscalculation must be performed weeklyduring the active life and closure periodof the unit, unless the RegionalAdministrator approves otherwise.Upon closure (installation of the finalcover for the unit), owners or operatorswill monitor the leak detection sumpmonthly, or in some cases quarterly orsemi-annually (see Section IV.D. forfurther discussion). While on a monthlymonitoring schedule, owners oroperators will have to convert themonitoring data to an average daily flowrate to determine if the action leakagerate has been exceeded. If an owner oroperator is monitoring quarterly or semi-annually no calculations are neededunless liquids are detected in the sumpabove the pump operating level, inwhich case the owner or operator mustresume monitoring the sump on amonthly basis. Such an owner oroperator would then have to convertmonitoring data to an average daily flowrate per acre for the purpose ofdetermining if the action leakage ratehas been exceeded.

2. Response Action Plan

The final rule requires owners oroperators of affected units to develop aresponse action plan for leaks exceedingthe action leakage rate § § 264.223,264.253, 264.304, 265.223, 265.259, and265.303). The response action plan is asite-specific plan that the owner oroperator develops to address leakagethrough the top liner to assure that itdoes not migrate out of the unit. It isbased on an assessment of thecapability of the total design,construction, and operation of the unitrather than of individual components ofthe unit.

The majority of commenters on theproposed response action planrequirements stated that there were toomany potential triggers (i.e.,leakagerates) that the response action plan mustpotentially address in the proposed rule.These commenters argued that thesetrigger levels lacked distinction as to theresponses they would necessitate. Other

commenters felt that the response actionplan requirements were confusing andinconsistent in certain cases. Thecommenters noted that many of theresponse actions for leaks above theproposed rapid and extremely largeleakage rate were similar tQ actions forleaks above the proposed action leakagerate. In response to these comments,EPA has simplified and clarified theresponse action requirements in today'sfinal rule.

The final rule specifies minimumresponse actions that the owner oroperator must take when the owner oroperator determines that the actionleakage rate has been exceeded. Theminimum response actions are includedin the response action plan that theowner or operator must prepare.Although minimum response actions arerequired to be in the response actionplan, the content of a response actionplan is determined by site-specificfactors. The minimum responsesrequired under today's rule are typicalof response action plans EPA hasidentified at operating facilities andincorporate comments EPA received onthe proposed response action planrequirements. Although today's rule onlyrequires the owner or operator to initiateresponse actions upon exceedance ofthe action leakage rate, owners oroperators may want to implement sometypes of response actions for leakagerates less than the action leakage rate,because these actions will lower theprobability that leakage will exceed theaction leakage rate and trigger today'sfinal response action requirements.

An owner or operator's responseaction plan must include notifying EPAwithin 7 days that the action leakagerate has been exceeded. EPA receivedno comments on the proposednotification requirement and thus, isfinalizing this requirement. The Agencyis also requiring that the owner oroperator submit a preliminary writtenassessment to the RegionalAdministrator within 14 days of thedetermination as to amount and sourceof the liquids in the detection sump,information on possible size, location,and cause of the leak, and anyimmediate and short term actions theowner or operator will take (e.g.,additional pumping and removal of theleachate, changes in operating practicesto reduce the leakage). As stated above,the Agency believes that exceedance ofthe action leakage rate is significant andindicates a major localized or generalfailure of the top liner, thus increasingthe potential for a buildup of head onthe bottom liner and increasing thepotential for migration of hazardous

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3476 Federal Register I Vol. 57, No. 19 / Wednesday, January 29, 1992 I Rules and Regulations

constituents into the bottom liner andout of the unit. For this reason, theAgency must be notified and given apreliminary assessment of the actionstaken by the owner or operator.

The focus of the response actionrequirements for flow rates above theaction leakage rate is the degree andschedule of what remediation, if any, isneeded to reduce the leakage to theaction leakage rate. The final rulerequires that owners or operatorsidentify the location, size, and cause ofthe leakage, and sample and analyze theleachate present in the detection sump.EPA believes that analyzing theleachate is necessary as part ofdetermining the response needed toreduce the leakage to below the actionleakage rate. For example, suchinformation may be useful in locating aleak at sites where different wastes aredisposed of in different cells. The owneror operators's's response action planmust discuss whether wastes should beremoved to locate and repair the leak,whether repairs or controls will be usedto minimize the leakage, and if so,whether operational changes, such asreduction or cessation of waste receipt,or partial or final closure of the unit, willbe implemented, and if so, what types.

Today's rule clarifies when the owneror operator must submit a reportdocumenting the response actions takenconcerning leakage above the actionleakage rate. The final rule requires thatthe owner or operator submit a report tothe Regional Administrator describinghow effective the response actions havebeen in reducing the leakage below theaction leakage rate and preventingmigration of hazardous constituents outof the unit within 30 days of exceedingthe action leakage rate. The final rulealso requires that the owner or operatorcontinue to submit these reportsmonthly as long as the action leakagerate is exceeded.

EPA received several comments onthe proposed response actionsubmission and approval process.Several commenters expressed concernover possible delays associated withrequiring a response action plan beforereceipt of waste. EPA receivedcomments both supporting and objectingto submittal of the response action planas part of the permit applicationprocess. One commenter suggested thatthe response action plan for bothleakage rates above the rapid andextremely large leakage rate andleakage rates above the proposed actionleakage rate but below the rapid andextremely large leakage rate should besubmitted as part of the permitapplication. Another commenter argued

against submittal as part of the permitapplication. The commenter stated thatthe bottom liner system can containleakage rates in excess of the rapid andextremely large leakage rate until theresponse action plan is approved, andthat such liquid would not migrate veryfar into the bottom liner before theresponse action plan was approved.

Unlike the proposed rule, the final rulerequires owners or operators to submitonly one response action plan forleakages exceeding the action leakagerate. Although EPA acknowledges thatthe bottom liner will provide initialcontainment of any leakage into the leakdetection system, EPA still feels thatleakage above the action leakage rate isan indication of a significant problemwith the unit. The Agency believes thata response action plan is necessarybefore receipt of the waste into a unit toassure that there is both a commitmentand an instrument in place to initiateresponses upon exceedance of theaction leakage rate, before leaks canpotentially migrate out of the unit.

The final rule requires that newhazardous waste management facilitiessubmit their response action plans andhave them approved as part of thepermit application process. Permittedfacilities must submit the plan as part ofa permit modification according to theprocedures in § 270.42. Consistent withthe minimum technology notificationrequirements of RCRA section 3015 forsurface impoundments and landfills,owners and operators of units at interimstatus facilities subject to today's leakdetection system rules are required tosubmit a response action plant inconjunction with the proposed actionleakage rate 60 days prior to receivingwaste into the unit.

D. Monitoring and InspectionRequirements

In today's final rule, EPA ispromulgating several minor amendmentsto monitoring and inspectionrequirements for new and replacementlandfills, surface impoundments, andwaste piles, and lateral expansions ofthese units. These amendments addinspection requirements for leakdetection systems (§§ 264.226, 264.254,264.303, 265.226, 265.260, and 265.304).Specifically, today's rule requiresfacility owners and operators to monitorthe sumps in leak detection systems forthe presence of liquids in the sumps andrecord the amount of liquid removedfrom the sumps. Under § § 264.222(b),264.252(b), 264.302(b), 265.222(c),265.255(c), and 265.302(c), owners oroperators must calculate the averagedaily flow rate in gpad for each leakdetection system sump on a weekly

basis during the active life and monihlvduring the post-closure period, whenmonthly monitoring is required, todetermine if the action leakage rate hasbeen exceeded.

In the May 29, 1987, proposal, EPAproposed to require daily monitoring ofthe leak detection system sump duringthe active life of the units, and weeklymonitoring during the post-closureperiod. EPA received several commentson the issue of the frequency of leakdetection system sump monitoringrequirements. Among those whocommented, several objected to therequirement for leak detection systemsump measurement on a daily basisduring the active life because (1) not allfacilities are operational on weekendsand holidays, and (2) the payment ofovertime rates to personnel formonitoring activities on weekends andholidays would be a significant financialburden. Other commenters stated that itwould be difficult to monitor manysumps on a daily basis, especially largesumps or facilities with small leakagerates. One commenter suggestedmonthly monitoring of the leak detectionsump. Most of these commenterssuggested that monitoring the sumpweekly during the active life wassufficient to determine exceedance of anaction leakage rate.

EPA maintains that precipitation orother events may lead to large heads onthe bottom liner over a period of a week,and that monthly monitoring of the sumpduring the active life is insufficient forobserving changes in liquid levels in thesump that may necessitate action on thepart of the owner or operator. However,EPA agrees with commenters that dailymonitoring of the sumps is excessivegiven that the Agency has redefined theaction leakage rate that triggers aresponse action. Thus, EPA has changedthe requirement from daily monitoring ofthe leak detection system sump torequire weekly monitoring during theactive life and closure period. Asdiscussed earlier, EPA has also changedthe requirement from daily removal ofaccumulated liquids in the sump to arequirement to remove liquids from thesump as necessary to minimize head onthe bottom liner (§ § 264.221(c)(3),264.251(c)(4), 254.301(c)(4), 265.221(a),265.254(a), and 265.301(a)).

Two commenters also objected to therequirement to monitor the leakdetection system sump weekly duringpost-closure. These commenters statedthat monthly monitoring would besufficient because the elimination ofliquids from incident precipitation andthe reduction of drainage from wasteswill result in insignificant leachate

No. 19 / Wednesday, January 29, 1992 / Rules and Regulations3476 Federal Register / Vol. 57,




generation in the years followingclosure. These commenters stated thatmonitoring should be conductedmonthly or quarterly and more oftenonly if the volumes of liquid in the sumpincreased.

EPA acknowledges that leachategeneration should decrease in the yearsfollowing closure of the unit, due to theeffectiveness of the final cover. Inresponse to comments received on thisissue, EPA is allowing owners oroperators to conduct monthlymonitoring of the sump after the finalcover is installed on the unit(§ § 264.226(d), 264.303(c), 265.226(c), and265.304(a)). The Agency has alsodecided in the final rule to allow ownersor operators to conduct quarterlymonitoring of the sumps during post-closure, if the liquid levels in the sumpstay below the pump operating level fortwo consecutive months, and/or semi-annual monitoring of the sumps if theliquid level in the sump stays below thepump operating level for twoconsecutive quarterly inspections.However, if pumping is required toremove liquids from the leak detectionsump (i.e., liquids above the operatinglevel of the sump) at any time duringquarterly or semi-annual inspections,owners or operators must increase theirmonitoring to a monthly or quarterlybasis, respectively. However, theAgency acknowledges that in somecases the levels may vary at facilitiesdepending on the design and geometryof the sump and the type of pump used.

The "pump operating level" is a levelproposed by the owner or operator andapproved by the Regional Administratorbased on sump dimensions, pumpactivation levels, and a level that avoidsbackup of liquids (from the sump anddrainage tile or pipes) into the drainagelayer.

Today's rule requires the owner oroperator to monitor for and record thepresence and level of liquids present ineach leak detection sump, as well as theamount of liquids removed from thesump, to determine the leakage ratethrough the top liner. The leachatevolume in the sump typically will bedetermined by measuring the liquidlevel in the sump. The leachate volumeremoved from the sump can bedetermined by collecting (in containers,tanks, etc.) and measuring the quantityof liquid pumped out of the sump or,alternatively, by installing flow-meteringequipment to record the volumes. Athird option is to install a device tomeasure inflow into the sump, for thoseunits where the sump is located outsidethe unit; this may be a weir or pump atthe sump inflow pipe. The leakage rate

is to be calculated as the volume ofliquid entering the sump over a period oftime divided by the time and then alsodivided by the unit area served by thesump.

EPA is today requiring, as proposed,that the measured leakage rate in eachsump in the leak detection system beused for determining whether the actionleakage rate for the unit has beenexceeded. EPA received severalcomments on this requirement. Thesecommenters maintained that a variancefrom the action leakage rate should beavailable when it can be demonstratedthat liquid in the leak detection systemis from a source other than leakagethrough the top liner. EPA acknowledgesthat the actual leakage rate through thetop liner may be different (larger orsmaller) than the measured leakage rateat the sump depending on: (1) Thecollection efficiency of the system and(2) the presence of water in the leakdetection system from construction,ground-water infiltration, consolidationof compacted soil liners, or additionalsources of liquid other than leakage.However, owners and operators mayconsider these other sources of liquidwhen determining an action leakage ratethat is appropriate for their unit and indeveloping their response action plan.

Today's final rule makes severaltechnical amendments to the generalinspection requirements and operatingrecord requirements for units affectedby today's rule. EPA today is amending§ 264.15 by correcting an earlieroversight by adding requirements toinspect hazardous waste tanks asrequired by § § 264.193 and 264.195(today's amendments also remove twoerroneous cross-references--§ § 264.194and 264.253-from § 264.15). Section265.15 is being amended by addingtoday's inspection requirements forunits at interim status facilities under§ § 265.260, 265.278, and 265.304. EPA isalso today making technical changes tothe operating record requirements forunits affected by today's rule atpermitted and interim status facilities in§§ 264.73 and 265.73. These sectionshave been modified to referencerecordkeeping requirements forpermitted tank facilities (in § § 264.191,264.193, and 264.195) and interim statustank facilities (in §§ 265.191, 265.193,and 265.195).

E. Construction Quality AssuranceEPA today is promulgating

construction quality assurancerequirements (CQA) for all newlandfills, surface impoundments, andwaste piles, and replacements andlateral expansions of such units to theextent they are affected by the double-

liner system and leak detection systemrequirements in today's rule. Today'sCQA requirements also apply, to theextent they are relevant to units builtunder variances granted under§ § 264.221, 264.251, 264.301, 265.221,265.254, and 265.301. The Agency hasconcluded that CQA is integral toensure the proper construction,operation, and design of double-linerand leak detection systems and theclosure of land disposal units. The CQArequirements being issued incorporatestandard engineering practices andcommon hazardous waste managementindustry practices that have alreadybeen proven to ensure that the designand performance standards of today'sfinal rule are met.

EPA is today promulgating CQArequirements applicable to foundations,dikes, low-permeability soil liners,geomembranes, leachate collection andremoval systems, leak detectionsystems, and final covers.

The Agency has conducted a numberof studies that outline the need for CQA.In 1983, EPA conducted a studyassessing existing technology for linerinstallation at hazardous waste landdisposal facilities ("Liner and LeakDetection Rule Background Document",1987). The data base used in the studyconsisted of information from theliterature supplemented by datacollected through 40 interviews withtechnical experts in industry, Stateregulatory agencies, trade andprofessional associations, researchorganizations, and waste managementcompanies. This study's conclusionswere: (1) Construction-related problemsduring liner system installationconstituted one of the major causes ofliner system failure and (2) a rigorousCQA program could have identified andcorrected many of the problems thatcontributed to such failure. The studyalso concluded that constructiontechniques that were available at thattime could be used to installgeomembrane and clay liner systemsthat met the Agency's performancestandards for liner systems. However,the study noted that a comprehensivemonitoring and audit program duringconstruction would be needed to attainthe Agency's performance standards forliner systems.

In 1985, EPA conducted another studyto supplement existing information onliner performance ("Liner and LeakDetection Rule Background Document",1987). This study was designed toevaluate the factors that contributed tosuccesses and failures at 27 landfills andsurface impoundments selected for casestudies. The results of this study showed

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that there were two main elementsrelated to successful liner installation.The first element was a properconceptual approach applied to allstages of unit construction, use, andclosure, including design, materialselection, contractor selection, linersystem installation, facility operation,and final cover design and installation.The second element was the extensiveuse of formal CQA programs to ensurethat the components of the unit wereconstructed properly in all stages of aunit's construction, The report statedthat a CQA program resulted in a betterconstructed liner system.

EPA data show the performance ofdouble liner systems and leachatecollection and removal/leak detectionsystems is greatly enhanced when CQAprocedures are implemented. Theimplementation of CQA proceduresresults in increased leachate collectionefficiency and reduces leakage throughboth synthetic and compacted soilliners. For example, informationcompiled in a recent report ("ActionLeakage Rates for Leak DetectionSystems", January, 1992) showed thatfrom a group of landfills withgeomembrane only top liners, 8 of 11landfill cells showed leakage ratesbelow 20 gpad when good CQA wasimplemented, as opposed to only I of 5landfill cells where CQA was notimplemented.

With the improved, consistent,performance of the double liner andleachate collection and removal systemcome significant environmental andpractical benefits. The resultantreduction in leakage rates through thetop and bottom liners reduces the threatof migration of hazardous constituentsto ground water, as is called for bysection 3004(o) of RCRA. The use ofCQA also may result in fewer costlyrepairs to land disposal units afterwaste has been received, feweroccasions when an action leakage rateis exceeded and implementation ofresponse action plans is necessary, anda diminished long-term need forcorrective action.

Today's requirements for CQA add aframework for requirements alreadyestablished in the regulations for CQAfor permitted landfill, surfaceimpoundment, and waste pileconstruction. Current requlations forthese units (§ § 264.226, 264.254, and264.303) already specify that syntheticand soil liners be inspected foruniformity, damage, and imperfectionsduring and immediately afterinstallation. The CQA requirementsbeing promulgated primarily addprocedures to ensure that the existing

general performance standards for CQAare met. Because the requirements oftoday's rule also apply to new units andlateral expansions and replacements ofexisting units at interim status facilities,today's CQA requirements also apply tothese units. The requirements beingpromulgated in § § 264.19 and 265.19 arein contrast to those in the May 29, 1987proposal, which would have put in placea substantial CQA program. EPA hasconcluded that the proposal was, in fact,redundant with existing guidancemanuals and also unduly prescriptiveand detailed with respect to methods,approaches, and documentation to theRegional Administrator.

The Agency is today continuing torely on available Agency guidancedocuments (instead of additionalregulations) to implument theperformance standards for constructionquality assurance of today's final rulebecause EPA believes that newertechnologies may be discouraged bydetailed regulations. Agency guidanceincludes guidelines for selecting specifictest methodologies and the number oftests that should be conducted duringinstallation, both of which will varysignificantly for different types of units,construction materials, and unitlocations. A final guidance document,entitled "Construction QualityAssurance for Hazardous Waste LandDisposal Facilities" (EPA 530-SW-86-031, October 1986), includes detailedguidance on the components of the CQArequirements of today's final rule.Additional guidance is also available inthe May 24, 1985 draft "MinimumTechnology Guidance on Double LinerSystems for Landfills and SurfaceImpoundments-Design, Construction,and Operation." Guidance fur theconstruction of clay liners is available inthe November, 1988 document entitled"Design, Construction, and Evaluation ofClay Liners for Waste ManagementFacilities" (EPA 530-SW-86-007F).

In today's final rule, EPA is requiringa site-specific construction qualityassurance plan to be prepared by theowner or operator of new landfills,surface impoundments, and waste piles,and replacements and lateralexpansions of such units (§ § 264.19(b)and 265.19(b)). This requirement is thesame as was proposed in the May 29,1987 proposed rule. EPA has concludedthat this plan is needed to ensure that ahazardous waste management unit isdesigned, constructed, operated, andclosed in accordance with the CQAprogram for the unit. Owners oroperators are required to prepare a CQAplan before constructing all new units,replacement units, and lateral

expansions of existing units at bothpermitted and interim status facilities.

The Agency received severalcomments objecting to two requirementsfor interim status facilities to submitdocumentation under the CQA program.These commenters objected to theproposed requirement that the owner oroperator submit, prior to construction, aCQA plan describing actions to be takento implement the CQA program. Thecommenters also objected to anassociated requirement to submit, priorto placing wastes in the unit, a CQAreport documenting compliance with theCQA plan. Many of these commentersfelt that these approval processes couldresult in unnecessary delays inconstruction of new units at interimstatus facilities. EPA agrees with thecommenters and is eliminating therequirement for interim status facilitiesto submit a CQA plan for approval. EPAis instead requiring that interim statusfacilities prepare a CQA plan andmaintain it onsite. By contrast,permitted facilities must submit a CQAplan as part of the Part B permitapplication; any changes to an approvedplan at a permitted facility wouldrequire a permit modification. Inaddition, the Agency is dropping therequirement for these interim statusfacilities to submit a CQA report andhas replaced this requirement with oneto submit a CQA certification(§ 265.19(d)). EPA is, however, reservingthe right to request supportingdocumentation for the certification. Thiscertification will ensure that CQAprocedures have been followed at thefacility. The certification must be signedby a registered professional engineerserving as a CQA officer, and must statethat the unit has been constructed inaccordance with the CQA plan andmeets the design specifications. Forunits at permitted facilities, thiscertification must be submitted by theowner or operator to the RegionalAdministrator and either approved orhave approval waived by the RegionalAdministrator under § 270.30(l)(2)(ii)prior to the receipt of waste. For units atinterim status facilities, the owner oroperator must submit this certificationat least 30 days prior to the receipt ofwaste; this will allow the RegionalAdministrator time to review thecertification, and if necessary, requestadditional information from the owneror operator. The owner or operator mayreceive wastes in the unit after 30 days,unless (1) the Regional Administratornotifies the owner or operator in writingthat the construction is unacceptable, (2)the Regional Administrator extends thereview period (by a maximum of 30



Federal Register / Vol. SV, 'No. 19 1 Wedresday, Jamary '29, 1992 J R les ard Regxfiws

days), or (3] the Regional Administratorrequests additional informatien withinthe 30-day period from submission d ftheCQA certification. The certificationofCQA activities for the 'final cover isa lready addressed in the overallcertification'required"for closureactivities under parts 64 and 265.

EPA is also specifically requiring theuse of a test fill for compacted soil linersas proposed in the May 29, 1987,proposed -rule. The test fill is an areadeveloped using the actual materials ofconstruction for 'he compacted soilcomponentof the bottom compositeliner to ensure that the liner isconstructed to meet ,design 'requirementsfor field permeability '(,I§ 264.19(c)(2)and 265.19(cJ(2)). The test fill will allowowners and operators, in'many cases, -toavoid the costs of faluresof the full-,scale 'unit by identifying problemsduring the test fill Bnalysis.

EPA received several comments onthe requiremertflor a lest ill. Somecommenters argued that a test -fill wasnot necessaTy, -Claiming 'that it isexpensive and'does not provide anybetter data 'han laboratory tests.'Onecommenter contended 'that fieldpermeability tests may be less -precisethan laboratorytests, because'the fieldtesting is subjected 'to more 'uncontrolledvariables 'e.g., weather conditions) thanlaboratory tests, and'therefore a test'filloften 'cannot be made to preciselyreplicateithe largeruait.

EPA disagrees, and is confident that,when functionally equivalentmaterialsa ad equipment eare used, v test Till canbe constructed 4o proVide -more acourateindicationdf futl-soade 'unit pefornmance.Receot data compiled from permitapplicants showsthat Wboratery studieshave dften not accurately'predicted 'fieldpermeability of 1he installed liner. TheAgency has found thdt oonstructed 'oilliners will sften'test well in'thelaboratory ibecause specimenpreparation ;actiVtties .Ie.g., ,oot removal,visual selection ds imfform sample,add tioMnl compactiowl have beenconducted on the 'laboratory sample.These lpreparation wctivfties are oftennot ackieved to 'the some -degree 'in elarge, field-scale operation. EPA hasfound thatt et'fill tooting using large-scale field tests .(esg., sealed'doubleuinginfiltrmdhni c etsntlyprovide amore accurate indicator 4f theperfarmamoaf a full acle unit than dolaboratory ieste.For'theme 'reasons, EPAconcludes That the tinformation gainedfrom field 4estinegsffetfl 1 is a mereediable icator of actual ifieldcondltiansihan~ilmestary tests, andsois stipulting the am safsfeid itesting fertest fills,-in Atr~s -rule. NIowever, ito

provide flexibility, today's final rilecontains a provion allowing for analternative demonstration whereavailable data are sufficientto clearlyshow that a 'onstructed soil finer willmeet design specifications te.g., test filldata from a soil liner constructed usingfunctionally equivalent materials andmethods of construction). The Agencybelieves that as more test fills areconstructed, this variance will becomemore achievable because more data willbe available. For units at permittedfacilities, this variance must be obtainedas part of the permitting process; forinterim status units, this variance is self-implementing. EPA is, however,reserving the Tight to review duringinspections documentation associatedwith variances claimed by owners oroperators of units at interim statusfacilities.

F. Implementation of Permitting'andInterim Status Requirements

Today's final rule amends the existingpart B permit a"plication requirementsin § § 27037, 279:16 and 270.21 -forsurface impoundments, waste pfles, andlandfills at facilities eeling -a CRApermit. These new provisions reqireowners or operators of such vnits'toprovide i6formation on low 'he linerand leak dotectionsystem wll 'bedesigned, ,constructed, 'operated, aondmaintained to meet herequirements ofpart 24. Tod's role aleso requiresowners or'opemtors-who proposeilternative designs for'double liner,leadhstev lolection and removalsystems, or lesk Aetectionveywtems 'tosubmit the appropriate-detailed ,lens,and engineering and bydrogedlogicreports idescribiM the etternativedesigns and operstingpraotices,including'pertinent looetion aspects. Inaddition, today's rule requires -the owneror operator to submit the proposedaction leakage rate, the Tesponse actionplan and the GQA plan for reviewin thepermitting Vrctess. Sections 270.17,270 18, and ,20;,Z letso.equire'ownersoroperators toproide a 4ecroienOfhow the to5k detection system willbeinapeted to e'et the requirements inpart 204. The -unit design, ation ledkegerate, response action plan,'CQA plan,monitoring provisions, and inspectionschedule vil become permit conditionsthat mustbe complied with lver e.-fifeof,the permit. lrk menmtoring andinspection item eomepart Sf theinspection schedule umdr 'I 4.l5b).

Currently permited failitias mt wreaffected by todays le imat.aukitpermit madifiations Ao EPA -under ikeprocedures sf 4 :27U42. 2ime the *M4rdh28, 1986 andMa'U,IU7V'prposels,EPA *w s, omtAgfftd emendments 'to

the procedures for permit modificafionsfor treatmen, 9torage, and disposalfacilities (53 FR 37912, September 28,1988). EPA will implement 'the newdouble-liner and leak detection systemrequirements using the new permitmodification procedures, consistent -withEPA policy (53 FR 37912, September 28,1988). Therefore, today's rule containsamendments to § 270.42 that categorizethe amended part 264 requirements ftoday's rule as various classes of permitmodifications.

tday's rule subjects owners andoperators of interim status facilties 'tothe same design and operatingrequirements as permitted facilities.However, procedural requirements for4documentation or reporting have beenstructured to be more self-implementingfor interim status facilities since thesefacilities have not yet been subjected tothe site~specific tailored standards of apermit. In today's rule, owners oroperators of interim status facilities thatare subject to today's requirements willfollow the same notification andapproval procedures existing for interimstatus surface impoundments andlandfills subjected to the minimumtechnological requirements in section3015 df CRA (§§ M5.221(b) and2 .=(b)).

Existing regulations require interim* status Tacilities to submit a -notice to -theRegional .Administrator at least6Odaysprior to reoeiving hazardous waste inunits sfftdld by'today7sequirements.In today's rule, EPA is requiring thatownersor operators submit heirproposed action kalcege xate endrespone action plan to the l'egioralAdministrator at 4east,0'deys pier itoreceiving hazardous waste in unitsaffected 'by today's requirements. 'oobjection orextension f the reviewtime is madeby ihe RegionalAdminitrtor, 'the 'prepemd actionleakage rate-and response action planare effective. In eddition,'EPA 'isrequiring.ower erqperators 'to sibmta certification Ithat the -mft has beenconstructed in accordene with 'the-CQAplan at least 30 days prier'te receivinghazardous waste in units affected bytoday's standards. If no objection orextension to 'the review 'time is made -bythe 'Regional Administrator' y 'he 'endof lthe iO-duy period,'the owner oroperator may receive wastes in -the unit.

lterim -status facilities are required'toprepare, but are not required to sbumit,the ir design end vperatinplans,monitoring lans, ar'QA plans prior;toreci tving wastes. These dorumerits mustbe'retned -nsite and be zvAdblei-orreview by the 'Reiondl Admitidtra'toT.EPA 's 'ot 'requiring'sdbmission 'and

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advance approval of this informationbecause such activities would beinconsistent with the goal of interimstatus to minimize review and approvalby the Regional Administrator.

V. State Authority

A. Applicability of Rule in AuthorizedStates

Under section 3006 of RCRA, EPAmay authorize qualified States toadminister and enforce the RCRAprogram within the State. Followingauthorization, EPA retains enforcementauthority under section 3008, 3013. and7003 of RCRA. although authorizedStates have primary enforcementresponsibility. The standards andrequirements for authorization are foundin 40 CFR part 271.

Prior to the Hazardous Solid WasteAmendments of 1984 (HSWA), a Statewith final authorization administered itshazardous waste program in lieu ofEPA's administering the Federalprogram in that State. The Federalrequirements no longer applied in theauthorized State, and EPA could notissue permits for any facilities that theState was authorized to permit. Whennew, more stringent Federalrequirements were promulgated orenacted, the State was obliged to enactequivalent authority within specifiedtime frames. New Federal requirementsdid not take effect in an authorizedState until the State adopted therequirements as State law and wasauthorized for the requirements.

In contrast, under RCRA section3006(g), new requirements andprohibitions imposed by HSWA takeeffect in authorized States at the sametime that they take effect in non-authorized States. EPA is directed tocarry out these requirements andprohibitions in authorized States,including the issuance of permits, untilthe State is granted authorization to doso. While States must still adoptHSWA-related provisions as State lawto retain final authorization, HSWA-based requirements apply in authorizedStates in the interim.

B. Effect on State Authorizations

Most of today's final rule for linersand leak detection systems is finalizedpursuant to RCRA sections 3004(o) and3015 which were added by HSWA. TheHSWA-based requirements are beingadded to Table 1 in 40 CFR 271.1(j),which identifies the Federal programrequirements that are promulgatedpursuant to HSWA and take effect in allStates, regardless of their authorizationstatus. As noted above, EPA willimplement those HSWA-based sections

of today's rule in authorized States untiltheir programs are modified to adoptthese rules and the modification isapproved by EPA. Because theserequirements are finalized pursuant toHSWA, a State submitting a programmodification may apply to receive eitherinterim or final authorization underRCRA section 3006(g)(2) or 3006(b),respectively, on the basis of staterequirements that are equivalent orsubstantially equivalent to EPA's. Theprocedures and schedule for Stateprogram modifications for either interimor finql authorization are described in 40CFR 271.21. The deadline by which theStates must modify their programs toadopt today's rule is July 1, 1993. Itshould be noted that HSWA interimauthorization will expire on January 1,1993 (see 40 CFR 271.24(c)).

Portions of today's rule at the timethey were proposed on May 29. 1987 (52FR 20220), were proposed to be adoptedpursuant to RCRA. As non-HSWA rules.therefore, they would not be effective inauthorized States until those Statesrevised their programs to adoptequivalent requirements under Statelaw. EPA has reconsidered this issueand now interprets the statute to allowmore of the rule, including the CQA,with the exception of its application tofinal cover requirements, to bepromulgated pursuant to HSWA.

EPA views today's CQA requirementsto be vital for liner and leak detectionsystems to perform as intended byHSWA, in section 3004(o), by effectivelypreventing the migration of hazardousconstituents into and through liners andfor detecting leaks of hazardousconstituents at the earliest practicabletime. The Agency has determined thatCQA at land disposal facilities improvesthe performance of liners and leakdetection systems. Specifically, test fillshave proven to be necessary forensuring that compacted soil linerssatisfy the permeability requirementsset by the statute. The response actionplans, based on detected leakage fromland disposal units are also consideredto be integral parts of the processestablished by section 3004(o) for earlydetection of liner breakthrough andprevention of migration of hazardousconstituents into the ground and surfacewater. Consequently, the Agency viewsthe CQA program and the responseaction plan (including the action leakagerate and monitoring to determine if theflow rate exceeds the action leakagerate) to be promulgated pursuant toHSWA for those units where the linerand leak detection standards arepromulgated pursuant to HSWA

New and replacement surfaceimpoundments and landfill units, and

lateral expansions of such units atfacilities for which a permit applicationwas received before November 8, 1984,are not explicitly addressed by section3004(o)(1)(A); however, these units arecovered by existing liner requirementswhich today are being revised by theAgency to take into accountimprovements in control technology.Thus these revisions are HSWA rulespursuant to section 3004(o)(1). Althoughsection 3004(o)(1)(A) does not requirewaste piles to meet the double liner andleachate collection system standards.existing regulations already containliner standards for waste piles and.therefore, pursuant to section 3004(o)(1).the Agency is revising the existingwaste pile regulations to take intoaccount improvements in controltechnology, As a result, the Agency isalso promulgating these double liner andleachate collection system standards forwaste piles as HSWA requirements Inaddition, the Agency views the linerrequirements for new waste piles asmandated by the form of leak detectionchosen for these regulations; andtherefore the liners standards from thispoint of view are also HSWArequirements. Leak detection forreplacement units and lateralexpansions of existing units (landfills,surface impoundments, and waste piles)at permitted facilities and at interimstatus waste piles are also being issuedas improvements in control andmeasurement technologies under section3004(o)(1) of RCRA.

CQA requirements for final covers a(both permitted and interim statusfacilities are promulgated pursuant tosection 3004(a) of RCRA, since finalcovers is not a HSWA requirement. TheCQA requirements for final covers.therefore, will not be effective inauthorized states. They will beapplicable only in those states that donot have authorization. In authorizedstates, the CQA requirements for finalcovers at permitted and interim statusfacilities will not be effective until thestate revises its program to adoptequivalent requirements under state lawand receives authorization by EPA forthem.

Section 40 CFR 271.21(e)(2) requiresStates that have final authorization tomodify their programs to reflect Federalprogram changes and to submit themodification to EPA for approval. Thedeadline by which the State mustmodify its program to adopt thisregulation is determined by thepromulgation date in accordance with 40CFR 271.21(e). These deadlines can beextended in certain cases (40 CFR271.21(e)(3)). Once EPA approves the



iFerded &tegi~Mr '/ 1. .5Y, 'No. -19 1 Wednesday, iwanary 29, -99 / Jfle emI Aeg tinu 2m

modification, ithe Sta e sequirementsbecome subtitle C.RCRAsequirements.

Authorized Shtrtes 2are onlyirequired tomodify their pragrms when EPApromulgates Federalregulations that aremore stringent or,boader in -scope thanthe existing Federal rqgulations. forthose Federal program changes that areless stringent orreduce the scopeof theFederalprogram,.States are not requiredto modify their programs. This is a jesultof section 3009-of RCRA, which allowsStates to impose regulations in additionto those in he Federad program. EPAhas determined 'ht-the liner and'leakdetection'systems rule is more -stringentthan the -existig federal regulations.ThereTore, anthorized'States arerequired to modify their programs toadopt regulations that are equivalent oroubstaytially-equivdlent.

States with authorized RCRAprogramsinW;aeady haverequirementssinilartolthose in today'srule. These StateTeguations hiawe notbeen assessed qainat the federalregulations beiqg TfiMlized .today todetermine whether they meet 4he testsfor authorization. Thus, a-State is notauthorized to implement theserequirements .in lieu ofEPAuntil theState program madification is approved.Of course, States with-existingstandards .ma , continue to administerand enforce their.standards as a matterof State law. In implementing theFederal program, EPA will work withStates under agreements to minimizeduplication of efforts. In many cases,EPA will be able to defer to the States intheir efforts-to implement theirprogramsrather than 'tke separate actions underFederal authority.

States thet submit official applicationsfor final authorization less Ithan 12months after the effective date of theseregulations are not required to includestandards equivalent to theseregulations in their application. Statesthat sulbmit,official-applioations forlinalauthorization 12 months after theeffective date of these regulations mustinclude standards equivalent to theseregdlations in'their application. Therequiremerrts a'State must meet whensubmitting its final authorizationapplication are set forth in 40 CFR 271.3.

WL. Regulatory Requirements

A. Economic Impact Analysis

Executive Order No. :12291 requiresthat regulatory agenoies determinewhether a new regflation constitutes amajor rulemaking .and, if-so, it-requiresthat the agenoy.oonduct a RegulatoryImpact Analysis [RIA). ,An RIA consistsof -the quantification of the potentialbenefits, costs, and economic impacts of

a major rule. A major rule is Aefined inExecutive Order No. 12291 as aregulation likely to result in:

e An annual effect on the economy of $100million oriore; or

* A majorincease incostsor-priceafor-consumers.,individuals. Industries, Federal,State, andlocal government agencies, orgeographic regions; or

* Stgnfficant-adverse fects oncompetition,-employmentinvestment,productivity,nnovation,,or on the-abilty ofUnited Statesibased enterprises to competewith foieigniased enterprisesm domestic orexport markets.

EPA-estimated the'effects df this ruleto determine,ff it is a major reg-tlation asdefined by Executive -Order. TheAgency's results indicate that the rilehas an anrnudl cost below $100Tillion.Furthermore, the Agency-does-notbelieve the rule will aignfficarTflyincrease costs for consumers,individuals, industries, federal, Stateand 'local -government agencies, orgeographic regions, or have significantadverse effects on competitionemployment, investment, innovation, orinternational'trade. Therefore, 1heAgency determines that the rule is not amajor ,rule.

Because the rule is not a majorrTule,EPA has performed an'Economic impadtAnalysis (EIA), focusing its analyses onthe insts and-economic impacts of therule only. The Agency's costanalysisindicates the annual incremertal costsof the rule will be approximatdly'$23million peryear (all costs are in "1990dollars).

1. Estimated Cost of the.Rdea. General approach. EPA estimated

incremental costs for provisions of -thefinal rule Which require new complianueactivities.'The incrementstl coat if -eachprovision was 'estimated *3 computingthe difference between'the -cost ofcomplying with the provision and thecost of complying with currentregulations (thebaseline formeasurement).'he baseline created by-current regulations includesrequirements imposed on hazardous'waste landfills, surface impoundments,and waste piles by the July 26, 1982permitting requirements for landdisposal facilities ((47 FR 32274) and the'July 15, 1985 Hazardous WasteIManagement System Final CodificationRule (50 FR 28702). These rules, takentogether, create baseline landfills hangsynthetic membrane top liners over aclay bottom liner with leachatecollection-systems :between the liners'and on top of the membrane -liner.Baseline surface impoundments are•constructed -Aimilarly, but .lak-theleachate collection system over the top

liner. Bueline we sie s -are aesumedto'be built with a sndle lay tinerbenea4h a leadhate -oollelion %yatm.

Inprojeicftghe cests-a'loda3sprovisimrs -EPA developed estimates eaffected plptflstions, -tmit costs dfcompliance, and ,ggrqgate costs nficompiance.SEetimates -of affectedpopulations were Ibased on thepermitted land disposal universe asreportedin the EPA HazardousWasteData Management 'ystem #t'DMt)and RCRIS Nvionral-OversightDatUBase '(October, 19'). Use d1 hepermitted universe was bused on'hefact that by November 8,79J8, "theAgency was required to permit all landdisposal 'facilitiesthat had submittedpermit applications by November B,'M84(HSWA section 3005{r)(21). thismandate'has resilted inthe permittfingOf nearly all f theland disposaluniverse. The data'base does ont.however, identify a very small futurepopulation that may be affectedlV 1heregulations being promulgated today(i.e., newly-regulated interim statusfacilities brought into the land disposaluniverse vie new xilemakingg). Thesenew interim status facilities, however,are expected to be offset by facilitiesdropping out of the RCRA Subtitle Cland disposal universe as a result ofregutory -jroram.

Unit cosits of-compliance, besel oncapftdl crets andoperating amdmsibtenanoe vcosts wre -developedusing'BPA's Uiner Location and'OestAnalysisModel. Bll diredt and indirectcosts were indrded. Aggregate costswere then Obtained -by muiltiolying-unitcosts by the numiber of units -in 1reaffected-poqmlgtion.Inhe tdal rule. costs 'from the .187

proposal ave been adjusted forinflation and are expressed in terms df1990 dollars. Also, cost estimates fromthe 1987 proposal have been adjusted toaccount for differences between theproposal and the final rule. Therefore,all costs related to permitted landtreatment units have been removed.Costs associated with thei nilementation of response action planshave been incorporated in the final rule.although EPAexpects that few facilitieswill exceed the action leakage ratewhich triggers response action. Inaddition, leak detection system unitcosts for surface impoundments havebeen adjusted upward-to -ocourt'for 4hehigher costs of higher-permeability(1 X 10- 1 cm/sec) drainage matedial,(this-cost-was-not-indluded in the costanalysis for Ae May 29, 1887 propesedrule). The CQA coats developedfr the4W -propol have -been -incorporated -inthis inal rule i'ra yois with -a few




modifications. First, costs used tocalculate certain CQA activities for testfills were adjusted upward to reflectnew cost information (See Section c.below). Second, an incremental cost of$400 per unit has been added to coverthe cost of a professional engineercertifying that each unit was constructedaccording to the CQA plan. Finally,CQA costs related to closure have beendeleted from the analysis. EPA believesowners and operators are routinelyperforming closure activities whencomplying with existing rules, whichrequire certification of closure by aregistered, professional engineer.Consequently, we do not believe theseCQA requirements representincremental costs attributable to thisrulemaking.

EPA used discounted cash flowanalysis to convert streams of costs overtime to equivalent annual costs over thelife of the facility. First, EPA convertedcost streams to present values asfollows:

n (costs)PV= I n

i=o (1 +r"

where the real rate of return (r) equals 3percent and n is the number of periodsin which costs are incurred. The cashflows do not include inflation, taxes, ordepreciation. As such, the present valuecosts report the full pre-tax compliancecosts in real terms assuming that anowner or operator can access capital ata real interest rate of 3 percent.

Second, in order to spread the costsevenly over the life of the facility, EPAannualized the present value costs bymultiplying them by a capital recoveryfactor (CRF):

r (r+ IOLCRF=

(r+ 1JOL- I

where OL is the operating life of thefacility. EPA assumed a 20-yearoperating life and a 3 percent real rate ofreturn, which leads to a CRF of 0.0672.The annualized value represents theannual revenue required to cover thecosts imposed by the provision. Thisvalue provides a consistent basis forpresenting and comparing costs ofdifferent provisions. However, itimplicitly assumes that facilities canpredict future costs and access capitalat a steady rate over the life of thefacility.

b. Double liner and leak detectionsystem. The final rule extends therequirements for double liners to wastepiles. The rule also requires the bottomliners of landfills, surfaceimpoundments, and waste piles to be acomposite liner and a leak detectionsystem to be installed above the bottomcomposite liner. The owner or operatoris also required to propose an actionleakage rate to serve as a trigger forresponse action and prepare a responseaction plan that would describeresponses to be initiated by the owneror operator when leakage through thetop liner exceeded the action leakagerate.

(1) Landfill cost analysis. Inestimating the cost of complying withthe composite bottom-liner and leakdetection system provisions, EPAassumed that the number of landfillswould remain equal to the currentnumber in the affected population andthat each unit would have a 20-yearoperating life and a 30-year post-closurecare period. This simplifying assumptionwas necessary due to lack of data on thecurrent and future number of new

landfill units, replacement units, andlateral expansions. EPA also assumedthat one cell would be opened andclosed each year during the 20-yearoperating life of a unit. EPA alsoassumed that landfill owners oroperators currently use double liners(but only a clay bottom liner) withleachate collection systems above andbetween the liners as required by theinterim statutory design requirements,codified in § § 264.301 and 265.301.

Based on facilities listed in theHWDMS and RCRIS National OversightData Base, the affected population wasfound to include 74 landfill facilitieseach with at least one unit, ranging insize from 500 MT/year to 150,000 MT/year. The affected population and thetotal incremental costs (above currentstatutory requirements) of the leakdetection system provisions are shownin Table 1. This figure includes anannual allowance for repair costssimilar to an insurance premium basedon an assumption that 5 percent of unitsof all types and sizes will experience aleak at some time during their 20-yearlife large enough to requireimplementation of the response actionplan. We believe the 5 percent rate is areasonable upper limit for properlyconstructed units, based on an analysisof flow rates in leak detection systemsat 82 landfill and surface impoundmentunits. Unit repair costs range from$28,000 for a 500 MT/year landfill to$6,100,000 for a 150,000 MT/year landfill(1990 dollars). EPA estimates that theincremental annualized costs forlandfills required to comply with theliner and leak detection systemprovisions would be approximately$4,850,000.

TABLE 1.-COST OF COMPLIANCE WITH DOUBLE LINER AND LEAK DETECTIONS SYSTEM PROVISIONS FOR LANDFILL UNITS

[1990 Dollars]

Incremental annualized Incremental annualized Allowance for repairs-- Annualized present Total costs per metricSize Number of active units present value unit cost present value total Aale p otal costs per metric($1,00) value total costs for all ton per year ($1,000)

($1,000) cost ($1,000) unitsi ($1,000)

500 mt/yr .......................................... 28 11.1 310.5 39.2 251,000 mt/yr ....................................... 8 14.6 116.5 22.4 172,000 mt/yr ...................................... 5 19.9 99.7 28.0 136,000 mt/yr ....................................... 12 37.2 446.2 168.0 915,000 mt/yr ..................................... 13 55.4 720.8 436.7 535,000 mt/yr ..................................... 4 98.0 392.0 302.4 560,000 mt/yr ..................................... 1 134.7 134.7 126.0 4100,000 mt/yr ................................... 1 194.3 194.3 207.2 4150,000 mt/yr ................................... 2 247.7 495.3 610.3 4

Subtotal .............................. 74 ............................................ 2910.1 1940.1 ............................................

Total . .. .............................. 4850.2 .................

Totals may not compute exactly due to roundoff.




(2) Surface Impoundment CostAnalysis. To estimate the cost of thecomplete bottom-liner and leakdetection system provisions, EPAassumed that the number of surfaceimpoundment units would remain equalto the current number in the affectedpopulation (except that no newimpoundments larger than 15 acreswould be constructed) and that eachunit would have a 20-year operating life.EPA also assumed that double liners(but only clay bottom liners) with aleachate collection system in betweenas required by the interim statutory

design requirements, codified in§ § 264.221 and 265.221 are currentlybeing used. We assumed that leachatecollection drainage media having apermeability of 10-2 cm/sec arecurrently being used. Based on facilitiesidentified in the data base, we estimatedthe affected population to include 329surface impoundment units at 143facilities. The units range in size from0.25 acres to 15 acres. The affectedpopulation and the total incrementalannualized costs (above currentstatutory requirements) of compliancewith the leak detection system

provisions are shown in Table 2. Aswith landfills, these costs include anallowance for repair costs based on anassumption that 5 percent will requirerepair during their 20-year life. Unitrepair costs range from $28,000 for a0.25-acre surface impoundment to$1,680,000 for a 15-acre unit (1990dollars). EPA estimates that theincremental annualized costs ofcomplying with the composite bottom-liner and leak detection systemprovisions would be approximately$2,650,000.

TABLE 2.-COST OF COMPLIANCE WITH DOUBLE LINER AND LEAK DETECTION SYSTEM PROVISIONS FOR SURFACE IMPOUNDMENT

UNITS

( 1990 Dollars]

Allowance for repairs-Incremental annualized Incremental annualized annualized present

Size Number of active units I present value unit cost present value total value total costs for all($1,000) cost 1 ($1,000) units ($1,000)2

0.25 AC ....................................................................................... 133 4.4 582.8 9.30.50 AC .................................................................................... 81 5.2 422.7 11.31.00 AC ........................................................................................ 44 7.2 314.8 12.32.00 AC ........................................................................................ 46 10.8 494.8 25.85.00 AC ....................................................................................... 18 22.0 395.3 25.215.00 AC ..................................................................................... 7 47.0 329.1 29.4

Subtotal ........................................................ 329 .............................................. 2539.5 113.3

T ota l ............................................................................................................................................................................ .............................................. 2652.8

Based on 2.3 impoundments per active facility.2 Totals may not compute exactly due to roundoff.

(3) Waste Pile Cost Analysis. EPAassumed that new, replacement, orexpanded waste piles would have toadd two geomembrane liners with a leakdetection system in between. Currentwaste pile regulations require only aclay liner with a leachate collectionsystem above. In estimating the cost ofcompliance with the double liner andleak detection system provisions, EPAassumed that the number of waste pileunits would remain the same as thecurrent number and that each unit

would have an operating life of 20 years.Based on facilities identified in the database, the affected population was foundto include 35 waste pile facilities rangingin size from 250 cubic feet to 1,000,000cubic feet.

The affected population and the totalincremental costs (above currentstatutory requirements) of compliancewith the double liner and leak detectionsystem provisions are shown in Table 3.As with landfills and surfaceimpoundments, this figure includes an

allowance for repair costs based on anassumption that a maximum of 5 percentwill require repair during their life. Unitrepair costs range from $5,600 for a 250-cubic-foot waste pile to $450,000 for a 1million-cubic-foot waste pile (1990dollars). EPA estimates that theincremental annualized costs ofcompliance with the double liner andleak detection system requirementswould be approximately $428,000.

TABLE 3.-COST OF COMPLIANCE WITH DOUBLE LINER AND LEAK DETECTION SYSTEM PROVISIONS FOR SURFACE WASTE PILE UNITS

[1990 Dollars]

Incremental annualized Incremental annualized Allowance for repairs-Inreentvalnu I annualized presentSize Number of active units I present value unit cost present value total value total costs for all($1,000) cost 2 ($1,000) units ($1.000)1

250 cu. ft ..................................................................................... 3 5.2 15.5 <0.11,000 cu. ft ................................................................................. 7 5.5 38.4 0.25,000 cu. ft .................................................................................. 7 6.5 45.5 0.325,000 cu. ft ......................................................... ..................... 6 8.6 51.7 0.5100.000 cu. ft .............................................................................. 5 12.9 64.4 1.0500.000 cu. ft .............................................................................. 3 24.4 73.3 2.11,000,000 cu. ft ........................................................................... 3 43.8 131.4 3.4

Subtotal .................................................................... 74 ............................................. 420.1 7.5

Total .................................. ......... ........................................... .............................................. ........................................... 427.6

'Outdoor (uncovered) waste piles.'Total may not compute exactly due to roundoff error.

3483



3484 Federal Register I Vol 57, No. 19 J Wednesday. January 29, 1992 / Rules and Regulations

c. CQA. The final rule would requirethe owner/operator to complete a CQAplan, implement the plan duringconstruction, and have a professionalengineer certify that construction wascompleted in accordance with the CQAplan. As noted above, costs estimatedfor the 1987 proposal were used in thisanalysis except additional costs wereadded for test fills and certification of aprofessional engineer, and specific costsassociated with closure were notincluded.

The proposed rule estimated that testfill costs would add about $10,000 (in

1987 dollars] to the cost of each facility.EPA has since determined that thisfigure is low and we have adjusted testfill costs upward to $50,000 (in 1990dollars) for all types of units. Tables 4.5,and 6 depict costs for implementingCQA (including test fills andconstruction certification) for landfills,surface Impoundments, and waste piles,respectively.

d. Total Incremental Costs of the LeakDetection System, CQA, and Double-Liner Requirements. The total costs ofthe leak detection system, CQA, anddouble liner provisions are shown in

Table 7 for landfills, sarfaceimpoundments, and waste piles. Thetotal incremental annualized cost of theprovisions would be approximately$7,930,000 for the leak detection systemand double liner requirements and$13,400,000 for CQA, for a total ofapproximately $21,300,000. Table 8compares the incremental costs fromthis ruelemaking with costs from the July15, 1965 codification rule and the July 26,198Z permitting rule.

TABLE 4.-COST OF COMPLIANCE WITH CONSTRUCTION QUALITY ASSURANCE PROVISIONS FOR LANDFILL UNITS

[1990 Dollars]

incremental annualized Incremental annualized Total costs per metricSize Number al active units present value unit cog pree value Wt6 ton per year ($1,000)($1,000) cost ($1,000)

500 mtyr ................ .. 28 114.1 3195.7 2301,000 mt/yr ............................................................................... 8 114.t 913.1 11.42,000 mt/yr ............................... 5 114.1 570.7 578.000 mt/yr ........... ..... 12 114.A 1369.6 t915,000 mt/yr .................... .. ....... 13 152.2 1979.2 835,000 mt/yr ............................ 4 154.7 08.9 460,000 mt/yr .............................. 1 2009 20R.9 3tO0,000 mt/yr ................. . . . ...... 1 20(9 20.9 2150,000 mt/yr ......................... .... 2 20&9 419.8 1

Total ............ ......................... 74 ............................ 9486. ...................................

I Totals may not compute exactly due to roundiff.

TABLE 5.-COST OF COMPLIANCE WITH CONSTRUCTION QUALITY ASSURANCE PROVISIONS FOR SURFACE IMPOUNDMENT UNITS

(1990 Dollars]

Incremental Incremental

Number of annualized annualizedactive units prese t value present valueunit cost tota Cosl 2.

(31,000) (1-,000)

0).25 A. .......................................................................................................... 58 23.6 t377.70.50 AC ............................ ............ .............. .............. 35 23.8 831.41.00 AC ..... ........................... ........................................................................ ... ....... . . .... .... .... ........... ......................... :...... 1t9 n o8 451235.00 AC .................................................................................................................................. ................. 8 29 23. ,5.615.00 ................ ............. .................................. 3 T32.00AC.............................. ::::::::::::::::::::::::::::::::::::::::::::::::: 20 29.8 4751.

1500AC................... ~. .. .- . .. .. .. . 3: 43.5 130.6

Total ........ ...................... . . ..................................... . ....... . ... . 1....................... 143 3W1.6

Based on 2.3 Impoundments per active facility.2 Totals may not compute exactly due to roundoff.

TABLE 6.-CosT OF COMPLIANCE WITH CONSTRUCTION QUALITY ASSURANCE PROVISIONS FOR WASTE PILE UNITS

(1990 Dollars]

Incremental Incremental

Size Number of annualized annualizedactive units I present value present value

uni cost total cost($1,000) ($1,000)

250 cu. ft ........................................................................................................................ .......................................................... 3 11.9 36.81,o00 cu. ft ............................ .............. . 7 11.95,000 cu.ft.............. ....... : ... .......................... ... 7 11.9 gs25.000 cu. ft ..................................................................................................................................................... 6 11.9 71.6100,000 cu. It ................. ........................................ ... .... ...................................... ................... .......................... ............... . 5 11.9 59.6500,000 cu. ft ......... ................ . ....- 3 11.9 35.8

1 000 cu. t................ ......... . ........ .... - -. ......- _... . . .......... ""..... ................... 3 11.9 35.8Total ........................... ...... ..................................................... ............................. 405.5

Outdoor (uncovered) waste piles.2 Totals may not compute exactly due to roundoff.




TABLE 7.-TOTAL COST OF COMPLIANCE WITH DOUBLE LINER, LEAK DETECTION SYSTEM, AND CQA PROVISIONS

[Incremental Annualized Present Value Cost in 1990 Dollars]

Liner/leak ConstructionFacility t detection quality Total ($1,000)system assurance

($1,000) ($1,000)

Landfill ............................................................................................................................................................................................. 4850.2 9486.6 14336.8Surface Impoundment .................................................................................................................................................................. 2652.8 3501.6 6154.5W aste Pile ...................................................................................................................................................................................... 427.6 405.5 833.1

Total ......................................................................................................................................................................................... 7930.6 13393.7 21324.3

Totals may not compute exactly due to roundoff.

TABLE 8.-INCREMENTAL COSTS OF DESIGN REQUIREMENTS

[In Millions of 1990 Dollars]

1982 liner/ 1985 Double-LCS liner Today's rule 4Facility type require- require-

ments 1.3 merits 2

.3

Landfill ............................................................................................................................................................................................. 13.8-27.0 4.5 14.3Surface Impoundment ................................................................................................................................................................... 10.4-40.9 11.9 6.2W aste Pile ....................................................................................................................................................................................... 0.5-09..................... 0.8

Total ......................................................................................................................................................................................... 24. 7-68.8 164 21.3

1 47 FR 32274.2 50 FR 28702.3 Incremental costs above previous Agency rules; costs adjusted to account for current number of units and 1990 dollars.4 Incremental costs above previous Agency rules. Costs do not consider potential savings due to use of 1% versus 2% minimum slope.

B. Regulatory Flexibility Act

The Regulatory Flexibility Act (RFA)of 1980 (Pub. L. 96-354) 5 U.S.C. 601 etseq., which amends the AdministrativeProcedure Act, requires Federalregulatory agencies to consider smallentities throughout the regulatoryprocess. The purposes of the RFA are todescribe the effects the regulations willhave on small entities and to examinealternatives that may reduce theseeffects. As indicated at proposal, EPAhas determined that today's rule will nothave a significant impact on asubstantial number of small entities.EPA conducted an evaluation of theimpacts of this rule on small businesses.For purposes of this analysis, EPA usedSmall Business Administration criteriafor identifying small businesses andevaluated the impact of today's ruleusing regulation-induced businessclosures as the key indicator ofregulatory impact. The test assumed thatany cost greater than 3 percent of totalassets per year will result in forcedclosures. EPA also considered a secondimpact measure that comparesincreased annual compliance costs tototal production costs with 5 percent ofthe threshold for significance. Usingthese tests, EPA has determined that theregulatory costs of today's rule will nothave a significant impact on asubstantial number of small entities.

C. Paperwork Reduction Act

The information collectionrequirements in this rule have beensubmitted for approval to the Office ofManagement and Budget (OMB) underthe Paperwork Reduction Act, 44 U.S.C.3501 et seq., and assigned OMB controlnumber ICR No. 995.06 as amended.These requirements are not effectiveuntil OMB approves them and atechnical amendment to that effect ispublished in the Federal Register. AnInformation Collection Requestdocument has been prepared by EPA(ICR No. 995.06) and a copy may beobtained from Sandy Farmer,Information Policy Branch, EPA, 401 MStreet, SW. (PM-223Y), Washington, DC20460 or by calling (202) 260-2740.

The public reporting burden for thiscollection of information is estimated toaverage 248 hours per response,including time for reviewinginstructions, searching existing datasources, gathering and maintaining therequired data, and completing andreviewing the collection of information.

Send comments regarding the burdenestimate or any other aspect of thiscollection of information, includingsuggestions for reducing this burden, toChief, Information Policy Branch, PM-223Y, U.S. Environmental ProtectionAgency, 401 M Street, SW., Washington,DC 20460; and to the Office ofInformation and Regulatory Affairs,Office of Management and Budget,

Washington, DC 20503, marked"Attention: Jonathan Gledhill."

VII. Supporting Documents

The following documents have beenprepared in support of this rulemakingand placed in docket number F-92LLDF-FFFFF.

1. U.S. EPA, "Liner and Leak DetectionRule Background Document", EPA/530-SW-87-015, May, 1987.

2. U.S. EPA, "Bottom Liner Performance inDouble-Lined Landfills and SurfaceImpoundments Background Document", EPA/530-SW-87-013, April, 1987.

3. U.S. EPA, "Compilation of CurrentPractices at Land Disposal Facilities",January, 1992.

4. U.S. EPA, "Action Leakage Rate for LeakDetection Systems", January, 1992.

5. U.S. EPA, "Response to Public Commentson Final Double-Liner and Leak DetectionRule", January, 1992.

6. U.S. EPA Memorandum, "Revisions toCost Analysis for the Final RulemakingEntitled Liners and Leak Detection Systemsfor Hazardous Waste Land Disposal Units,'January, 1992.

List of Subjects in 40 CFR Parts 260, 264,265, 270, and 271

Administrative practice andprocedure, Confidential businessinformation, Hazardous materialstransportation, Hazardous waste, Indianlands, Intergovernmental relations,Penalties, Insurance, Packaging andcontainers, Reporting and recordkeepingrequirements, Security measures. Surety

3485



3486 Federal Register I VoL 57, No. 19 J Wednesday, January 29, 1992 / Rules and Regulations

bonds, Water pollution control, Watersupply.

Dated: January 15, 192.William K. Reily,Administrator.

For the reasons set out in thepreamble, chapter I of title 40 of theCode of Federal Regulations is amendedas follows:

PART 260-HAZARDOUS WASTEMANAGEMENT SYSTEM: GENERAL

1. The authority citation for part 260continues to read as follows:

Authority: 42 U.S.C. 6905, 6912(a), 6921-6927, 6930, 6934, 6935, 6937, 6938, 6939, and6974.

2. Section 260.10 is amended byadding the definition of "replacementunit" in alphabetical order, and revisingthe definition of "sump" to read asfollows:

§ 260.10 Definitions.

Replacement unit means a landfill,surface impoundment, or waste pile unit(1) from which all or substantially all ofthe waste is removed, and (2) that issubsequently reused to treat, store, ordispose of hazardous waste."Replacement unit" does not apply to aunit from which waste is removedduring closure, if the subsequent reusesolely involves the disposal of wastefrom that unit and other closing units orcorrective action areas at the facility, inaccordance with an approved closureplan or EPA or State approvedcorrective action.* a * * *

Sump means any pit or reservoir thatmeets the definition of tank and thosetroughs/trenches connected to it thatserve to collect hazardous waste fortransport to hazardous waste storage,treatment, or disposal facilities; exceptthat as used in the landfill, surfaceimpoundment, and waste pile rules,"sump" means any fined pit or reservoirthat serves to collect liquids drainedfrom a leachate collection and removalsystem or leak detection system forsubsequent removal from the system.

PART 264-STANDARDS FOROWNERS AND OPERATORS OFHAZARDOUS WASTE TREATMENT,STORAGE, AND DISPOSALFACILITIES

1. The authority citation for part 264continues to read as foffows:

Authority: 42 U.S.C. 6906 6912a), 6924, and6925.

2. Section 264.15 is amended byrevising paragraph (b)(4) to read asfollows:.

§ 264.15 General Inspection requirements.* * * * *

(b) * *(4) The frequency of inspection may

vary for the items on the schedule.However, it should be based on the rateof deterioration of the equipment andthe probability of an environmental orhuman health incident if thedeterioration, malfunction, or anyoperator error goes undetected betweeninspections. Areas subject to spills, suchas loading and unloading areas, must beinspected daily when in use. At aminimum, the inspection schedule mustinclude the items and frequencies calledfor in § § 264.174, 264.193, 264.195,264.226, 264.254, 264.278, 264.303, 264.347,264.602, 264.1033, 264.1052, 264.1053, and264.1058, where applicable.

3. Subpart B is amended by adding§ 264.19 as follows:

§ 264.19 Construction quality assuranceprogram.

(a) COA program. (1) A constructionquality assurance (CQAI program isrequired for all surface impoundment,waste pile, and landfill units that arerequired to comply with § § 264.221 (c)and (d), 264.251 (c) and (d), and 264.301(c) and (d). The program must ensurethat the constructed unit meets orexceeds all design criteria andspecifications in the permit. Theprogram must be developed andimpilemented under the direction of aCQA officer who is a registeredprofessional engineer.

(2) The CQA program must addressthe following physical components,where applicable:

(i) Foundations;(ii) Dikes;(iii) Low-permeability soil liners;(iv) Geomembranes (flexible

membrane liners);(v) Leachate collection and removal

systems and leak detection systems; and(vi) Final cover systems.(b) Written CQA plan. The owner or

operator of units subject to the CQAprogram under paragraph (a) of thissection must develop and implement awritten CQA plan. The plan mustidentify steps that will be used tomonitor and document the quality ofmaterials and the condition and mannerof their installation. The CQA plan mustinclude:

(1) Identification of applicable units,and a description of how they will beconstructed.

(2) Identification of key personnel inthe development and implementation ofthe CQA plan, and CQA officerqualifications.

(3) A description of inspection andsampling activities for all unitcomponents identified in paragraph(a)(2) of this section, includingobservations and tests that will be usedbefore, during, and after construction toensure that the construction materialsand the installed unit components meetthe design specifications. Thedescription must cover: Sampling sizeand locations; frequency of testing; dataevaluation procedures; acceptance andrejection criteria for constructionmaterials; plans for implementingcorrective measures; and data or otherinformation to be recorded and retainedin the operating record under § 264.73.

(c] Contents ofprogram. (1) The CQA-program must include observations,inspections, tests, and measurementssufficient to ensure:

(i} Structural stability and integrity ofall components of the unit identified inparagraph (a)(2] of this section;

(ii) Proper construction of allcomponents of the liners, leachatecollection and removal system, leakdetection system, and final coversystem, according to permitspecifications and good engineeringpractices, and proper installation of allcomponents (e.g.. pipes} according todesign specifications;

(iii) Conformity of all materials usedwith design and other materialspecifications under § § 264.221, 264.251.and 264.301.

(2) The CQA program shall includetest fills for compacted soil liners, usingthe same compaction methods as in thefull scale unit. to ensure that the linersare constructed to meet the hydraulicconductivity requirements of§§ 264.221(c](1)(i)(B), 264.251(c)(11(i}{BJ,and 264.301(c)(1)(i)(B) in the field.Compliance with the hydraulicconductivity requirements must beverified by using in-situ testing on theconstructed test fill. The RegionalAdministrator may accept an alternativedemonstration, in lieu of a test fill,where data are sufficient to show that aconstructed soil liner will meet thehydraulic conductivity requirements of§ § 264.221(cf1(i)(B, 264.251(c)(1)(i(B,and 264.301(c)(I}i){B} in the field.

(d) CertificaLioa. Waste shall not bereceived in a unit subject to § 264.19until the owner or operator hassubmitted to the Regional Administratorby certified mail or hand delivery acertification signed by the CQA officerthat the approved CQA plan has beensuccessfully carried out and that the unit




meets the requirements of § § 264.221 (c)or (d), 264.251 (c) or (d), or 264.301 (c) or(d); and the procedure in § 270.30(I)(2)(ii)of this chapter has been completed.Documentation supporting the CQAofficer's certification must be furnishedto the Regional Administrator uponrequest.

4. Section 264.73 is amended byrevising paragraph (b)(6) to read asfollows:

§ 264.73 Operating record.* * *, * *

(b) ***(6) Monitoring, testing or analytical

data, and corrective action whererequired by subpart F and § § 264.19,264.191, 264.193, 264.195, 264.222, 264.223,264.226, 264.252-264.254, 264.276, 264.278,264.280, 264.302-264.304, 264.309, 264.347,264.602, 264.1034(c)-264.1034(f), 264.1035,264.1063(d)-264.1063(i), and 264.1064.

5. Section 264.221 is amended byredesignating paragraphs (1), (g), and (h)as paragraphs (g), (h), and (i),respectively; by revising paragraphs (c)and (d); and by adding new paragraph(f) to read as follows:

§ 264.221 Design and operatingrequirements.

(c) The owner or operator of each newsurface impoundment unit on whichconstruction commences after January29, 1992, each lateral expansion of asurface impoundment unit on whichconstruction commences after July 29,1992 and each replacement of anexisting surface impoundment unit thatis to commence reuse after July 29,1992must install two or more liners and aleachate collection and removal systembetween such liners. "Constructioncommences" is as defined in § 260.10 ofthis chapter under "existing facility".

(1)(i) The liner system must include:(A) A top liner designed and

constructed of materials (e.g., ageomembrane) to prevent the migrationof hazardous constituents into such linerduring the active life and post-closurecare period; and

(B) A composite bottom liner,consisting of at least two components.The upper component must be designedand constructed of materials (e.g., ageomembrane) to prevent the migrationof hazardous constituents into thiscomponent during the active life andpost-closure care period. The lowercomponent must be designed andconstructed of materials to minimize themigration of hazardous constituents if abreach in the upper component were tooccur. The lower component must beconstructed of at least 3 feet (91 cm) of

compacted soil material with ahydraulic conductivity of no more thanlx1o/-'/ cm/sec.

(ii) The liners must comply withparagraphs (a) (1), (2), and (3) of thissection.

(2) The leachate collection andremoval system between the liners, andimmediately above the bottomcomposite liner in the case of multipleleachate collection and removalsystems, is also a leak detection system.This leak detection system must becapable of detecting, collecting, andremoving leaks of hazardousconstituents at the earliest practicabletime through all areas of the top linerlikely to be exposed to waste orleachate during the active life and post-closure care period. The requirementsfor a leak detection system in thisparagraph are satisfied by installation ofa system that is, at a minimum:

(i) Constructed with a bottom slope ofone percent or more;

(ii) Constructed of granular drainagematerials with a hydraulic conductivityof 1x10/-/ cm/sec or more and athickness of 12 inches (30.5 cm) or more;or constructed of synthetic or geonetdrainage materials with a transmissivityof 3xlo/-'/ msec or more;

(iii) Constructed of materials that arechemically resistant to the wastemanaged in the surface impoundmentand the leachate expected to begenerated, and of sufficient strength andthickness to prevent collapse under thepressures exerted by overlying wastesand any waste cover materials orequipment used at the surfaceimpoundment;

(iv) Designed and operated tominimize clogging during the active lifeand post-closure care period; and

(v) Constructed with sumps and liquidremoval methods (e.g., pumps) ofsufficient size to collect and removeliquids from the sump and preventliquids from backing up into thedrainage layer. Each unit must have itsown sump(s). The design of each sumpand removal system must provide amethod for measuring and recording thevolume of liquids present in the sumpand of liquids removed.

(3) The owner or operator shall collectand remove pumpable liquids in thesumps to minimize the head on thebottom liner.

(4) The owner or operator of a leakdetection system that is not locatedcompletely above the seasonal highwater table must demonstrate that theoperation of the leak detection systemwill not be adversely affected by thepresence of ground water.

(d) The Regional Administrator mayapprove alternative design or operating

practices to those specified in paragraph(c) of this section if the owner oroperator demonstrates to the RegionalAdministrator that such design andoperating practices, together withlocation characteristics:

(1) Will prevent the migration of anyhazardous constituent into the groundwater or surface water at least aseffectively as the liners and leachatecollection and removal system specifiedin paragraph (c) of this section; and

(2) Will allow detection of leaks ofhazardous constituents through the topliner at least as effectively.

(f) The owner or operator of anyreplacement surface impoundment unitis exempt from paragraph (c) of thissection if:

(1) The existing unit was constructedin compliance with the design standardsof sections 3004 (o)(1)(A)[i) and (o)(5) ofthe Resource Conservation andRecovery Act; and

(2) There is no reason to believe thatthe liner is not functioning as designed.

6. New § § 264.222 and 264.223 areadded to read as follows:

§ 264.222 Action leakago rate.(a) The Regional Administrator shall

approve an action leakage rate forsurface impoundment units subject to§ 264.221 (c) or (d). The action leakagerate is the maximum design flow ratethat the leak detection system (LDS) canremove without the fluid head on thebottom liner exceeding 1 foot. Theaction leakage rate must include anadequate safety margin to allow foruncertainties in the design (e.g., slope,hydraulic conductivity, thickness ofdrainage material), construction,operation, and location of the LDS,waste and leachate characteristics,likelihood and amounts of other sourcesof liquids in the LDS, and proposedresponse actions (e.g., the action leakagerate must consider decreases in the flowcapacity of the system over timeresulting from siltation and clogging, riblayover and creep of syntheticcomponents of the system, overburdenpressures, etc.).

(b) To determine if the action leakagerate has been exceeded, the owner oroperator must convert the weekly ormonthly flow rate from the monitoringdata obtained under § 264.226(d) to anaverage daily flow rate (gallons per acreper day) for each sump. Unless theRegional Administrator approves adifferent calculation, the average dailyflow rate for each smp must becalculated weekly during the active lifeand closure period, and if the unit is

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closed in accordance with § 264.228(b),monthly during the post-closure careperiod when monthly monitoring isrequired under § 264.226(d).

§ 264.223 Response actions.(a) The owner or operator of surface

impoundment units subject to § 264.221(c) or (d) must have an approvedresponse action plan before receipt ofwaste. The response action plan mustset forth the actions to be taken if theaction leakage rate has been exceeded.At a minimum, the response action planmust describe the actions specified inparagraph (b) of this section.

(b) If the flow rate into the leakdetection system exceeds the actionleakage rate for any sump, the owner oroperator must:

(1) Notify the Regional Administratorin writing of the exceedence within 7days of the determination;

(2) Submit a preliminary writtenassessment to the RegionalAdministrator within 14 days of thedetermination, as to the amount ofliquids, likely sources of liquids,possible location, size, and cause of anyleaks, and short-term actions taken andplanned;

(3) Determine to the extent practicablethe location, size, and cause of any leak;

(4) Determine whether waste receiptshould cease or be curtailed, whetherany waste should be removed from theunit for inspection, repairs, or controls,and whether or not the unit should beclosed;

(5) Determine any other short-termand longer-term actions to be taken tomitigate or stop any leaks; and

(6) Within 30 days after thenotification that the action leakage ratehas been exceeded, submit to theRegional Administrator the results of theanalyses specified in paragraphs (b) (3),(4), and (5) of this section, the results ofactions taken, and actions planned.Monthly thereafter, as long as the flowrate in the leak detection systemexceeds the action leakage rate, theowner or operator must submit to theRegional Administrator a reportsummarizing the results of any remedialactions taken and actions planned.

(c) To make the leak and/orremediation determinations inparagraphs (b) (3), (4), and (5) of thissection, the owner or operator must:

(1)(i) Assess the source of liquids andamounts of liquids by source,

(ii) Conduct a fingerprint, hazardousconstituent, or other analyses of theliquids in the leak detection system toidentify the source of liquids andpossible location of any leaks, and thehazard and mobility of the liquid; and

(iii) Assess the seriousness of anyleaks in terms of potential for escapinginto the environment; or

(2) Document why such assessmentsare not needed.

7. Section 264.226 is amended byadding new paragraph (d) to read asfollows:

§ 264.226 Monitoring and Inspection.

(d)(1) An owner or operator requiredto have a leak detection system under§ 264.221 (c) or (d) must record theamount of liquids removed from eachleak detection system sump at leastonce each week during the active lifeand closure period.

(2) After the final cover is installed,the amount of liquids removed fromeach leak detection system sump mustbe recorded at least monthly. If theliquid level in the sump stays below thepump operating level for twoconsecutive months, the amount ofliquids in the sumps must be recorded atleast quarterly. If the liquid level in thesump stays below the pump operatinglevel for two consecutive quarters, theamount of liquids in the sumps must berecorded at least semi-annually. If atany time during the post-closure careperiod the pump operating level isexceeded at units on quarterly or semi-annual recording schedules, the owneror operator must return to monthlyrecording of amounts of liquids removedfrom each sump until the liquid levelagain stays below the pump operatinglevel for two consecutive months.

(3) "Pump operating level" is a liquidlevel proposed by the owner or operatorand approved by the RegionalAdministrator based on pump activationlevel, sump dimensions, and level thatavoids backup into the drainage layerand minimizes head in the sump.

8. Section 264.228 is amended byredesignating paragraphs (b)(2) and(b)[3) as paragraphs (b)(3) and (b)(4)respectively, and by adding a newparagraph (b)(2) to read as follows:

§ 264.228 Closure and post-closure care.

(b)(2) Maintain and monitor the leak

detection system in accordance with§§ 264.221(c)(2)(iv) and (3) and264.226(d), and comply with all otherapplicable leak detection systemrequirements of this part;

9. Section 264.251 is amended byredesignating paragraphs (c), (d), (e), (f),and (g) as paragraphs (g), (h), (i), (j) and(k), respectively, and by adding newparagraphs (c), (d), (e), and (f0 to read asfollows:

§ 264.251 Design and operatingrequirements.* * * * *

(c) The owner or operator of each newwaste pile unit on which constructioncommences after January 29, 1992, eachlateral expansion of a waste pile unit onwhich construction commences afterJuly 29, 1992, and each replacement ofan existing waste pile unit that is tocommence reuse after July 29, 1992 mustinstall two or more liners and a leachatecollection and removal system aboveand between such liners. "Constructioncommences" is as defined in § 260.10under "existing facility".



(B) A composite bottom liner,consisting of at least two components.The upper component must be designedand constructed of materials (e.g., ageomembrane) to prevent the migrationof hazardous constituents into thiscomponent during the active life andpost-closure care period. The lowercomponent must be designed andconstructed of materials to minimize themigration of hazardous constituents if abreach in the upper component were tooccur. The lower component must beconstructed of at least 3 feet (91 cm) ofcompacted soil material with ahydraulic conductivity of no more than1X10 - 7 cm/sec.

(ii) The liners must comply withparagraphs (a)(1)(i), (ii), and (iii) of thissection.

(2) The leachate collection andremoval system immediately above thetop liner must be designed, constructed,operated, and maintained to collect andremove leachate from the waste pileduring the active life and post-closurecare period. The Regional Administratorwill specify design and operatingconditions in the permit to ensure thatthe leachate depth over the liner doesnot exceed 30 cm (one foot). Theleachate collection and removal systemmust comply with paragraphs (c)(3)(iii)and (iv) of this section.

(3) The leachate collection andremoval system between the liners, andimmediately above the bottomcomposite liner in the case of multipleleachate collection and removalsystems, is also a leak detection system.This leak detection system must becapable of detecting, collecting, andremoving leaks of hazardousconstituents at the earliest practicabletime through all areas of the top liner




likely to be exposed to waste orleachate during the active life and post-closure care period. The requirementsfor a leak detection system in thisparagraph are satisfied by installation ofa system that is, at a minimum:


(ii) Constructed of granular drainagematerials with a hydraulic conductivityof 1X 10-2 cm/sec or more and athickness of 12 inches (30.5 cm) or more;or constructed of synthetic or geonetdrainage materials with a transmissivityof 3 X10-5 m2 /sec or more:

(iii) Constructed of materials that arechemically resistant to the wastemanaged in the waste pile and theleachate expected to be generated, andof sufficient strength and thickness toprevent collapse under the pressuresexerted by overlying wastes, wastecover materials, and equipment used atthe waste pile;



(4) The owner or operator shall collectand remove pumpable liquids in the leakdetection system sumps to minimize thehead on the bottom liner.


(d) The Regional Administrator mayapprove alternative design or operatingpractices to those specified in paragraph(c) of this section if the owner oroperator demonstrates to the RegionalAdministrator that such design andoperating practices, together withlocation characteristics:

(1) Will prevent the migration of anyhazardous constituent into the groundwater or surface water at least aseffectively as the liners and leachatecollection and removal systemsspecified in paragraph (c) of this section;and


(e) Paragraph (c) of this section doesnot apply to monofills that are granted a

waiver by the Regional Administrator inaccordance with I 264.221(e).

(f) The owner or operator of anyreplacement waste pile unit is exemptfrom paragraph (c) of this section if:

(1) The existing unit was constructedin compliance with the design standardsof section 3004(o)(1)(A)(i) and (o)(5) ofthe Resource Conservation andRecovery Act; and


10. New § 264.252 and 264.253 areadded to read as follows:

§ 264.252 Action leakage rate.(a) The Regional Administrator shall

approve an action leakage rate forsurface impoundment units subject to§ 264.251(c) or (d}. The action leakagerate is the maximum design flow ratethat the leak detection system (LDS) canremove without the fluid head on thebottom liner exceeding I foot. Theaction leakage rate must include anadequate safety margin to allow foruncertainties in the design (e.g.. slopehydraulic conductivity, thickness ofdrainage material), construction.operation, and location of the LDSwaste and leachate characteristicslikelihood and amounts of other source,of liquids in the LDS. and proposedresponse actions (e.g. the action leakagerate must consider decreases in the flewcapacity of the system over timeresulting from siltation and clogging, riblayover and creep of syntheticcomponents of the system. overburdenpressures, etc.).

(b) To determine if the action leakagerate has been exceeded, the owner oroperator must convert the weekly flowrate from the monitoring data obtainedunder I 264.254(c) to an average dailyflow rate (gallons per acre per day) foreach sump. Unless the RegionalAdministrator approves a differentcalculation, the average daily flow ratefor each sump must be calculatedweekly during the active life and closureperiod

§ 264.253 Response actions.(a) The owner or operator of waste

pile units subject to 1 264.251 (c) or (d)must have an approved response actionplan before receipt of waste. Theresponse action plan must set forth theactions to be taken if the action leakagerate has been exceeded. At a minimum,the response action plan must describethe actions specified in paragraph (b) ofthis section.


(1) Notify the Regional Administratorin writing of the exceedance within 7days of the determination;



(4) Determine whether waste receiptshould cease or be curtailed, whetherany waste should be removed from theunit for inspection, repairs, or controls,and whether or not the dnit should beclosed;

(5) Determine any other short-termand long-term actions to be taken tomitigate or stop any leaks; and

(6) Within 30 days after thenotification that the action leakage ratehas been exceeded, submit to theRegional Administrator the results of theanalyses specified in paragraphs (b) (3),14). and (5) of this section, the results ofactions taken. and actions planned.Monthly thereafter. as long as the flowrate in the leak detection systemexceeds the action leakage rate, theowner or operator must submit to theRegional Administrator a reportsummarizing the results of any remedialactions taken and actions planned.

1c) To make the leak and/orremediation determinations inparagraphs (b) (3), (4), and (5) of thissection, the owner or operator must:





11. Section 264.254 is amended byadding new paragraph (c) to read asfollows:


(c) An owner or operator required tohave a leak detection system under§ 264.251(c) must record the amount ofliquids removed from each leakdetection system sump at least onceeach week during the active life andclosure period.

12. Section 264.301 is amended byredesignating paragraphs (f), (g), (i), (i),

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(j), and (k) as paragraphs (g), (h), (i), (j),(k), and (I), respectively, by revisingparagraphs (c) and (d), and by addingnew paragraph (f) to read as follows:

§ 264.301 Design and operatingrequirements.* * * * *t

(c) The owner or operator of each newlandfill unit on which constructioncommences after January 29, 1992, eachlateral expansion of a landfill unit onwhich construction commences afterJuly 29, 1992, and each replacement ofan existing landfill unit that is tocommence reuse after July 29, 1992 mustinstall two or more liners and a leachatecollection and removal system aboveand between such liners. "Constructioncommences" is as defined in § 260.10 ofthis chapter under "existing facility".



(B) A composite bottom liner,consisting of at least two components.The upper component must be designedand constructed of materials (e.g., ageomembrane) to prevent the migrationof hazardous constituents into thiscomponent during the active life andpost-closure care period. The lowercomponent must be designed andconstructed of materials to minimize themigration of hazardous constituents if abreach in the upper component were tooccur. The lower component must beconstructed of at least 3 feet (91 cm) ofcompacted soil material with ahydraulic conductivity of no more thanIX10O 7 cm/sec.

(ii) The liners must comply withparagraphs (a)(1) (i), (ii), and (iii) of thissection.

(2) The leachate collection andremoval system immediately above thetop liner must be designed, constructed,operated, and maintained to collect andremove leachate from the landfill duringthe active life and post-closure careperiod. The Regional Administrator willspecify design and operating conditionsin the permit to ensure that the leachatedepth over the liner does not exceed 30cm (one foot). The leachate collectionand removal system must comply withparagraphs (3)(c) (iii) and (iv) of thissection.

(3) The leachate collection andremoval system between the liners, andimmediately above the bottomcomposite liner in the case of multipleleachate collection and removalsystems, is also a leak detection system.This leak detection system must be

capable of detecting, collecting, andremoving leaks of hazardousconstituents at the earliest practicabletime through all areas of the top linerlikely to be exposed to waste orleachate during the active life and post-closure care period. The requirementsfor a leak detection system in thisparagraph are satisfied by installation ofa system that is, at a minimum:


(ii) Constructed of granular drainagematerials with a hydraulic conductivityof 1X10- 2 cm/sec or more and athickness of 12 inches (30.5 cm) or more;or constructed of synthetic or geonetdrainage materials with a transmissivityof 3 X10- 5m 2/sec or more;

(iii) Constructed of materials that arechemically resistant to the wastemanaged in the landfill and the leachateexpected to be generated, and ofsufficient strength and thickness toprevent collapse under the pressuresexerted by overlying wastes, wastecover materials, and equipment used atthe landfill;



(4) The owner or operator shall collectand remove pumpable liquids in the leakdetection system sumps to minimize thehead on the bottom liner.


(d) The Regional Administrator mayapprove alternative design or operatingpractices to those specified in paragraph(c) of this section if the owner oroperator demonstrates to the RegionalAdministrator that such design andoperating practices, together withlocation characteristics:

(1) Will prevent the migration of anyhazardous constituent into the groundwater or surface water at least aseffectively as the liners and leachatecollection and removal systemsspecified in paragraph (c) of this section;and


(f0 The owner or operator of anyreplacement landfill unit is exempt fromparagraph (c) of this section if:



13. New § 264.302 is added to read asfollows:

§ 264.302 Action leakage rate.(a) The Regional Administrator shall

approve an action leakage rate forsurface impoundment units subject to§ 264.301(c) or (d). The action leakagerate is the maximum design flow ratethat the leak detection system (LDS) canremove without the fluid head on thebottom liner exceeding I foot. The actionleakage rate must include an adequatesafety margin to allow for uncertaintiesin the design (e.g., slope, hydraulicconductivity, thickness of drainagematerial), construction, operation, andlocation of the LDS, waste and leachatecharacteristics, likelihood and amountsof other sources of liquids in the LDS,and proposed response actions (e.g., theaction leakage rate must considerdecreases in the flow capacity of thesystem over time resulting from siltationand clogging, rib layover and creep ofsynthetic components of the system,overburden pressures, etc.).

(b) To determine if the action leakagerate has been exceeded, the owner oroperator must convert the weekly ormonthly flow rate from the monitoringdata obtained under § 264.303(c), to anaverage daily flow rate (gallons per acreper day) for each sump. Unless theRegional Administrator approves adifferent calculation, the average dailyflow rate for each sump must becalculated weekly during the active lifeand closure period, and monthly duringthe post-closure care period whenmonthly monitoring is required under§ 264.303(c).

14. Section 264.303 is amended byadding new paragraph (c) to read asfollows:


(c)(1) An owner or operator requiredto have a leak detection system under§ 264.301(c) or (d) must record theamount of liquids removed from eachleak detection system sump at least




once each week during the active lifeand closure period.


(3) "Pump operating level" is a liquidlevel proposed by the owner or operatorand approved by the RegionalAdministrator based on pump activationlevel, sump dimensions, and level thatavoids backup into the drainage layerand minimizes head in the sump.

15. New § 264.304 is added to read asfollows:

§ 264.304 Response actions.(a) The owner or operator of landfill

units subject to § 264.301(c) or (d) musthave an approved response action planbefore receipt of waste. The responseaction plan must set forth the actions tobe taken if the action leakage rate hasbeen exceeded. At a minimum, theresponse action plan must describe theactions specified in paragraph (b) of thissection.







(6) Within 30 days after thenotification that the action leakage ratehas been exceeded, submit to theRegional Administrator the results of theanalyses specified in paragraphs (b)(3),(4), and (5] of this section, the results ofactions taken, and actions planned.Monthly thereafter, as long as the flowrate in the leak detection systemexceeds the action leakage rate, theowner or operator must submit to theRegional Administrator a reportsummarizing the results of any remedialactions taken and actions planned.

(c) To make the leak and/orremediation determinations inparagraphs (b)(3), (4), and (5) of thissection, the owner or operator must:





16. Section 264.310 is amended byredesignating paragraphs (b)(3), (4), and(5) as paragraphs (b)(4), (5), and (6)respectively, and by adding a newparagraph (b)(3) to read as follows:


(b) * * *(3) Maintain and monitor the leak

detection system in accordance with§§ 264.301(c)(3)(iv) and (4) and264.303(c), and comply with all otherapplicable leak detection systemrequirements of this part;

PART 265-INTERIM STATUSSTANDARDS FOR OWNERS ANDOPERATORS OF HAZARDOUS WASTETREATMENT, STORAGE, ANDDISPOSAL FACILITIES

1. The authority citation for Part 265 isrevised to read as follows:

Authority: 42 U.S.C. 6905, 6912(a), 6924,6925, 6935, and 6936.

2. Section 265.15 is amended byrevising paragraph (b)(4) to read asfollows:

§ 265.15 General Inspection requirements.( b * *

{b) * * *

(4] The frequency of inspection mayvary for the items on the schedule.However, it should be based on the rateof deterioration of the equipment andthe probability of an environmental orhuman health incident if thedeterioration, malfunction, or anyoperator error goes undetected betweeninspections. Areas subject to spills, suchas loading and unloading areas, must beinspected daily when in use. At aminimum, the inspection schedule mustinclude the items and frequencies calledfor in § § 265.174, 265.193, 265.195,265.226, 265.260, 265.278, 265.304, 265.347,265.377, 265.403, 265.1033, 265.1052,265.1053, and 265.1058, whereapplicable.* * * * *

3. Subpart B is amended by adding§ 265.19 to read as follows:

§ 265.19 Construction quality assuranceprogram.

(a) CQA program. (1) A constructionquality assurance (CQA) program isrequired for all surface impoundment,waste pile, and landfill units that arerequired to comply with §§ 265.221(a),265.254, and 265.301(a). The programmust ensure that the constructed unitmeets or exceeds all design criteria andspecifications in the permit. Theprogram must be developed andimplemented under the direction of aCQA officer who is a registeredprofessional engineer.

(2) The CQA program must addressthe following physical components,where applicable:

(i) Foundations;(ii) Dikes;(iii) Low-perneability soil liners;(iv) Geomembranes (flexible

membrane liners);(v) Leachate collection and removal

systems and leak detection systems; and(vi) Final cover systems.(b) Written CQ.A plan. Before

construction begins on a unit subject tothe CQA program under paragraph (a) ofthis section, the owner or operator mustdevelop a written CQA plan. The planmust identify steps that will be used tomonitor and document the quality ofmaterials and the condition and mannerof their installation. The CQA plan mustinclude:

(1) Identification of applicable units,and a description of how they will beconstructed.

(2) Identification of key personnel inthe development and implementation ofthe CQA plan, and CQA officerqualifications.

(3) A description of inspection andsampling activities for all unitcomponents identified in paragraph

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(a)(2) of this section, includingobservations and tests that will be usedbefore, during, and after construction toensure that the construction materialsand the installed unit components meetthe design specifications. Thedescription must cover: Sampling sizeand locations; frequency of testing dataevaluation procedures; acceptance andrejection criteria for constructionmaterials; plans for implementingcorrective measures; and data or otherinformation to be recorded and retainedin the operating record under § 265.73.

(c) Contents of program, (1) The CQAprogram must include observations,inspections, tests, and measurementssufficient to ensure:

(i) Structural stability and integrity ofall components of the unit identified inparagraph (a){2) of this section;

(ii) Proper construction of allcomponents of the liners. leachatecollection and removal system, leakdetection system, and final coversystem, according to permitspecifications and good engineeringpractices, and proper installation of allcomponents (e.g., pipes) according todesign specifications;

(iii) Conformity of all materials usedwith design and other materialspecifications under § § 264.221, 264.251,and 264.301 of this chapter.

(2] The CQA program shall includetest fills for compacted soil liners, usingthe same compaction methods as in thefull-scale unit, to ensure that the linersare constructed to meet the hydraulicconductivity requirements of§§ 264.221(c)(1), 264.251(c)(1), and264.301(c)(1) of this chapter in the field.Compliance with the hydraulicconductivity requirements must beverified by using in-situ testing on theconstructed test fill. The test fillrequirement is waived where data aresufficient to show that a constructed soilliner meets the hydraulic conductivityrequirements of § § 264.221(c)(1),264.254(c)(1), and 264.301(c)(1) of thischapter in the field.

(d) Certification. The owner oroperator of units subject to § 265.19must submit to the RegionalAdministrator by certified mail or handdelivery, at least 30 days prior toreceiving waste, a certification signedby the CQA officer that the CQA planhas been successfully carried out andthat the unit me-ets the requirements of§ § 265.221(a), 2J5.254, or 265.301(a). Theowner or operator may receive waste inthe unit after 30 days from the RegionalAdministrator's receipt of the CQAcertification unless the RegionalAdministrator determines in writing thatthe construction is not acceptable, orvv ends the review period for a

maximum of 30 more days, or seeksadditional Information from the owneror operator during this period.Documentation supporting the CQAofficer's certification must be furnishedto the Regional Administrator uponrequest.

4. Section 265.73 is amended byrevising paragraph (b)[6) to read asfollows:

§ 265.73 Operating record.}* * ***

(b)* *

(6) Monitoring, testing, or analyticaldata, and corrective action whererequired by subpart F and § 1 265.19,265.90, 265.94, 265.191, 265.193, 265.195,265.222, 265.223, 265.226, 265.255, 265.259.265.260, 265.276, 265.278, 265.280(d)(1),265.302-265.304, 265.347, 265.377,265.1034(c)-65.1034(f), 265.1035,265.1063(d)-264.1063(i), and 265.1064.* * * ,*

5. Section 265.221 is amended byrevising the section heading and byrevising paragraphs (a) and (c) to readas follows:


(a) The owner or operator of each newsurface impoundment unit on whichconstruction commences after January29,1992, each lateral expansion of asurface impoundment unit on whichconstruction commences after July 29,1992, and each replacement of anexisting surface impoundment unit thatis to commence reuse after July 29, 1992must install two or more liners and aleachate collection and removal systembetween such liners, and operate theleachate collection and removal system,in accordance with § 264.221(c), unlessexempted under I 264.221(d), (e), or (0,of this chapter. "Constructioncommences" is as defined in § 260.10 ofthis chapter under "existing facility."

(c) The owner or operator of anyreplacement surface impoundment unitis exempt from paragraph (a) of thissection if:

(1) The existing unit was constructedin compliance with the design standardsof § 3004(o)(1](A)(i) and (o)(5) of theResource Conservation and RecoveryAct; and


6. Paragraphs (a] and (b) of § 265.222are transferred to § 265.221 andredesignated as paragraphs (f) and (g),respectively.

7. Section 265.222, is amended byrevising, the section heading and adding

paragraphs (a) through {c) and § 265.223is added to read as follows:

§ 265.222 Action leakage rate.(a) The owner or operator of surface

impoundment units subject to§ 265.221(a) must submit a proposedaction leakage rate to the RegionalAdministrator when submitting thenotice required under § 265.221(b).Within 60 days of receipt of thenotification, the Regional Administratorwill: Establish an action leakage rate,either as proposed by the owner oroperator or modified using the criteria inthis section; or extend the review periodfor up to 30 days. If no action is taken bythe Regional Administrator before theoriginal 60 or extended 90 day reviewperiods, the action leakage rate will beapproved as proposed by the owner oroperator.

(b) The Regional Administrator shallapprove an action leakage rate forsurface impoundment units subject to§ 265.221(a). The action leakage rate isthe maximum design flow rate that theleak detection system (LDS) can removewithout the fluid head on the bottomliner exceeding I foot. The actionleakage rate must include an adequatesafety margin to allow for uncertaintiesin the design (e.g., slope, hydraulicconductivity, thickness of drainagematerial), construction, operation, andlocation of the LDS. waste and leachatecharacteristics, likelihood and amountsof other sources of liquids in the LDS,and proposed response actions (e.g., theaction leakage rate must considerdecreases in the flow capacity of thesystem over time resulting from siltationand clogging, rib layover and creep ofsynthetic components of the system,overburden pressures, etc.).

(c) To determine if the action leakagerate has been exceeded, the owner oroperator must convert the weekly ormonthly flow rate from the monitoringdata obtained under § 265.226(b), to anaverage daily flow rate (gallons per acreper day) for each sump. Unless theRegional Administrator approves adifferent calculation, the average dailyflow rate for each sump must becalculated weekly during the active lifeand closure period, and if the unit closesin accordance with § 265.228(a)(2).monthly during the post-closure careperiod when monthly monitoring isrequired under § 265.226(b).

§ 265.223 Response actions.(a) The owner or operator of surface

impoundment units subject to§ 265.221(a) must submit a responseaction plan to the RegionalAdministrator when submitting the




proposed action leakage rate under§ 265.222. The response action plan mustset forth the actions to be taken if theaction leakage rate has been exceeded.At a minimum, the response action planmust describe the actions specified inparagraph (b) of this section.







(6) Within 30 days after thenotification that the action leakage ratehas been exceeded, submit to theRegional Administrator the results of theanalyses specified in paragraphs (b)(3),(4), and (5) of this section, the results ofactions taken, and actions planned.Monthly thereafter, as long as the flowrate in the leak detection systemexceeds the action leakage rate, theowner or operator must submit to theRegional Administrator a reportsummarizing the results of any remedialactions taken and actions planned.






B. Section 265.226 is amended byrevising the section heading and addingnew paragraph (b) to read as follows:


(b)(1) An owner or operator requiredto have a leak detection system under§ 265.221(a) must record the amount ofliquids removed from each leakdetection system sump at least onceeach week during the active life andclosure period.


(3) "Pump operating level" is a liquidlevel proposed by the owner or operatorand approved by the RegionalAdministrator based on pump activationlevel, sump dimensions, and level thatavoids backup into the drainage layerand minimizes head in the sump. Thetiming for submission and approval ofthe proposed "pump operating level"will be in accordance with § 265.222(a).

9. Section 265.228 is amended byredesignating paragraphs (b)(2) and (3)as paragraphs (b)(3) and (4)respectively, and by adding a newparagraph (b)(2) to read as follows:


(b) * * *(2) Maintain and monitor the leak

detection system in accordance with§§ 265.221(c)(2)(iv) and (3) of thischapter and 265.226(b) and comply withall other applicable leak detectionsystem requirements of this part;

10. Section 265.254 is revised,including the section heading, to read asfollows:


The owner or operator of each newwaste pile on which constructioncommences after January 29, 1992, eachlateral expansion of a waste pile unit onwhich construction commences afterJuly 29, 1992, and each such replacement

of an existing waste pile unit that is tocommence reuse after July 29, 1992 mustinstall two or more liners and a leachatecollection and removal system aboveand between such liners, and operatethe leachate collection and removalsystems, in accordance with§ 264.251(c), unless exempted under§ 264.251(d), (e), or (f), of this chapter;and must comply with the procedures of§ 265.221(b). "Construction commences"is as defined in § 260.10 of this chapterunder "existing facility".

11. New § § 265.255, 265.259, and265.260 are added to read as follows:

§ 265.255 Action leakage rates(a) The owner or operator of waste

pile units subject to § 265.254 mustsubmit a proposed action leakage rate tothe Regional Administrator whensubmitting the notice required under§ 265.254. Within 60 days of receipt ofthe notification, the RegionalAdministrator will: Establish an actionleakage rate, either as proposed by theowner or operator or modified using thecriteria in this section; or extend thereview period for up to 30 days. If noaction is taken by the RegionalAdministrator before the original 60 orextended 90 day review periods, theaction leakage rate will be approved asproposed by the owner or operator.

(b) The Regional Administrator shallapprove an action leakage rate forsurface impoundment units subject to§ 265.254. The action leakage rate is themaximum design flow rate that the leakdetection system (LDS) can removewithout the fluid head on the bottomliner exceeding 1 foot. The actionleakage rate must include an adequatesafety margin to allow for uncertaintiesin the design (e.g., slope, hydraulicconductivity, thickness of drainagematerial), construction, operation, andlocation of the LDS, waste and leachatecharacteristics, likelihood and amountsof other sources of liquids in the LDS,and proposed response actions (e.g., theaction leakage rate must considerdecreases in the flow capacity of thesystem over time resulting from siltationand clogging, rib layover and creep ofsynthetic components of the system,overburden pressures, etc.).

(c) To determine if the action leakagerate has been exceeded, the owner oroperator must convert the weekly flowrate from the monitoring data obtainedunder § 265.260, to an average daily flowrate (gallons per acre per day) for eachsump. Unless the RegionalAdministrator approves a differentcalculation, the average daily flow ratefor each sump must be calculated

3493




weekly during the active life and closureperiod.

§ 265.259 Response actions.(a) The owner or operator of waste

pile units subject to [ 265.254 mustsubmit a response action plan to theRegional Administrator when submittingthe proposed action leakage rate under§ 265.255. The response action plan mustset forth the actions to be taken if theaction leakage rate has been exceeded.At a minimum, the response action planmust describe the actions specified inparagraph (b) of this section.

(b) If the flow rate into the leakdetermination system exceeds theaction leakage rate for any sump, theowner or operator must:




(4) Determine whether waste receiptsshould cease or be curtailed, whetherany waste should be removed from theunit for inspection, repairs, or controls,and whether or not the unit should beclosed;


(6) Within 30 days after thenotification that the action leakage ratehas been exceeded, submit to theRegional Administrator the results of theanalyses specified in paragraphs (b)(3),(4), and (5) of this section, the results ofactions taken, and actions planned.Monthly thereafter, as long as the flowrate in the leak detection systemexceeds the action leakage rate, theowner or operator must submit to theRegional Administrator a reportsummarizing the results of any remedialactions taken and actions planned.



(ii) Conduct a fingerprint, hazardousconstituent, or other analyses of theliquids in the leak detection system toidentify the source of liquids andpossible location of any leaks, and thehazard and mobility of the liquid, and



§ 265.260 Monitoring and Inspection.An owner or operator required to

have a leak detection system under§ 265.254 must record the amount ofliquids removed from each leakdetection system sump at least onceeach week during the active life andclosure period.

12. Section 265.301 is amended byrevising the section heading and byrevising paragraphs (a) and (c) to readas follows:


(a) The owner or operator of each newlandfill unit on which constructioncommences after January 29, 1992, eachlateral expansion of a landfill unit onwhich construction commences afterJuly 29, 1992 and each replacement ofan existing landfill unit that is tocommence reuse after July 29, 1992 mustinstall two or more liners and a leachatecollection and removal system aboveand between such liners, and operatethe leachate collection and removalsystems, in accordance with§ 264.301(d), (e), or (f), of this chapter."Construction commences" Is as definedin § 260.10 of this chapter under"existing facility".

(c) The owner or operator of anyreplacement landfill unit is exempt fromparagraph (a) of this section if:



13. Paragraphs (a], (b), (c), and (d) of§ 265.302 are transferred to § 265.301and redesignated as paragraphs (f), (g),(h), and (i), respectively.

14. Section 265.302, Is amended byrevising the section heading and addingparagraphs (a) through (c) and new§ § 265.303 and 265.304 are added to readas follows:

§ 265.302 Action leakage rate.(a) The owner or operator of landfill

units subject to § 265.301(a) must submita proposed action leakage rate to theRegional Administrator when submittingthe notice required under § 265.301(b).Within 60 days of receipt of thenotification, the Regional Administratorwill: Establish an action leakage rate,

either as proposed by the owner oroperator or modified using the criteria inthis section; or extend the review periodfor up to 30 days. If no action is taken bythe Regional Administrator before theoriginal 60 or extended 90 day reviewperiods, the action leakage rate will beapproved as proposed by the owner oroperator.

(b) The Regional Administrator shallapprove an action leakage rate forsurface impoundment units subject to§ 265.301(a). The action leakage rate isthe maximum design flow rate that theleak detection system (LDS) can removewithout the fluid head on the bottomliner exceeding 1 foot. The actionleakage rate must include an adequatesafety margin to allow for uncertaintiesin the design (e.g., slope, hydraulicconductivity, thickness of drainagematerial), construction operation. andlocation of the LDS, waste and leachatecharacteristics, likelihood and amountsof other sources of liquids in the LDS,and proposed response actions (e.g., theaction leakage rate must considerdecreases in the flow capacity of thesystem over time resulting from siltationand clogging, rib layover and creep ofsynthetic components of the system,overburden pressures, etc.).

(c) To determine if the action leakagerate has been exceeded, the owner oroperator must convert the weekly ormonthly flow rate from the monitoringdata obtained under § 265.304 to anaverage daily flow rate (gallons per acreper day] for each sump. Unless theRegional Administrator approves adifferent calculation. the average dailyflow rate for each sump must becalculated weekly during the active lifeand closure period, and monthly duringthe post-closure care period whenmonthly monitoring is required under§ 265.304(b).

§ 265.303 Response actions.(a) The owner or operator of landfill

units subject to § 265.301(a) must submita response action plan to the RegionalAdministrator when submitting theproposed action leakage rate under§ 265.302. The response action plan mustset forth the actions to be taken if theaction leakage rate has been exceeded.At a minimum, the response action planmust describe the actions specified inparagraph (b) of this section.





Federal Regist ,Ve1. 57, No. 19 1 Wednesday, january 29, 1992 J Rules and Rqgulations 3495

(2) Submit a preliminary writtenassessment to the RegionalAdministrator within 14 days of thedetermination, as -to the amount ofliquids, likely sources of liquids,possible location, size, and cause of anyleaks. and short-term actions taken aadplanned;



(5) Determine any other short-termand longer-4erm actions to be taken tomitigate or stop any leaks; and

(6) Within 30 days after thenotification that the action leakage ratehas been exceeded, submit to theRegional Administrator the results of theanalyses specified in paragraphs (b)(3),(4), and .) of i section, the results ofactions taken, and actions planned.Monthly thereafter, as long as the fowrate in the leak detection sysitmexceeds the action leakage rate. theowner or operator must submit to theRegional Administrator a reportsummarizing the results of any remedialactions taken and actions planned.

(c) To make the leak and/orremediation determinations inparagraphs 1b)(3), (4), and (5)'of thissection, the owner or operator must:

(1)(i) Assess the source of liquids andamountsof liquids by source,

(ii) Conduct a fingerrint, hazwdousconstituent. or other analyses of theliquids in the leak detection system toidentify the source of liquids andpossible location of any leaks, and thehazard and mobility of the liquid- and

(iii) Assess the seriousness of anyleaks in terms of potent l for escapinginto the environment or


§ 26.304 montorlm an Inspection.(a) An owner or operator required to

have a leak detection system under§ 265.301(a) must record the amount ofliquids removed from each leakdetection system sump at least onceeach week during the active life andclosure period.

(b) After the final cover is installed,the amouni of liquids removed fromeach leak detection system sump mustbe recorded at least monthly. Itheliquid level tn the sump stays below thepump operating leve4 for twoconsecutive months, the amount ofliquids in the sumpaimust berecorded atleast quarterly. If the liquid level in thesump stays below the pump operating

level for two consecutive quarters, theamount of liquids in 4he sumps must berecorded at least semibannually. If atany time during the post-dosure careperiod the pump operating level isexceeded at units on quaitefly or semi-annual recording schedules, the owneror operator must return to monthlyrecording of amounts of tiquids removedfrom each sump until the liquid levelagain stays below the pump operatinglevel for two consecutive months.

(c) "Pump operating level" is a 'liquidlevel proposed by the owner or operatorand approved by the RegionalAdministrator based on pump activationlevel, sump dimensions, and level thatavoids backup into the drainage layerand minimizes head in the sump. Thetiming for submission and approval ofthe proposed "pump operating level"will be in accordance with § 265.30Z(a).

15. Section 265.310 is amended byredesignating paragraphs (b)(2), 13), and(4) as paragraphs (b)(3), 14), and (5),respectively, and by adding a newparagraph (b)(2) to read as follows:

§ 26.310 Ckmu and post-dosur care.

(b) * "(2) Maintain and monitor the leak

detection system in accordance with§ § 364.301(q)c3f{iv) and (4) of thischapter and 25.30), and comply withall other applicable leak detectionsystem requirements of this part:

PART 270--EPA ADMINISTEREDPERMIT PROGRAMS: THEHAZARDOUS WASTE PERMITPROGRAM


Anuwhorlt 42 U..C &M0,512 WA2, 06=56927,6939, and 6974.

2. Section 270.4 -is amended byrevising paragraph (a) to read asfollows:

1 270.4 Effect efa Permit.fa) Compliance with a RCRA permit

during its term constitutes compliance,for purposes of enforcement, withsubtitle C of RCRA except for thoserequirements not included in the permitwhich:

(1) Become effective by statute;(2) Are promulSated under pat 2W of

this chapter restcicting the placement ofhazardous wastes in or on the land or

(3) Are pornilUted under r ii4 ofthis chapter regardiv leak detectionsystems for new and replacementsurface impoundment, waste pile, andlandfill units, and lateral expansions ofsurface impoundment, waste pile, and

landfill -units. The leak detection systemrequirements include double liners,CQA programs, monitoring, actionleakage rate, and reaponse actionplans, and will be implemented throughthe procedures of 1 270A2 Class 1"permit modifications.

(3) Section 27(07 is amended byredesignating paragrh (it(Z) and (3)as (b)() aW ) respectively; revisingparagraph jib); introductory text; addingparagraphs (h)t2j through (b(5); andrevising paragraph {) -to -mad asfollows:

§ 270.17 Specific Part B Informationrequirements for surface Impoundments.

(b) Detailed plans and an engineerngreport descrtibing bow the surfaceimpoundment is designed and is or willbe constructed, opezated, andmaintained to meet the -r'quiramems of§ § 264.19,8m4.2 ,24.22, and 2.223of this chapter, addressing theuollowingitems:

(1) . * A

(2) The double liner and leak(leachate) detection, collection, andremoval system, if the surfaceimpoundment must meet therequirements of 1 284.221(p) -of thischapter. If an exemption from therequirements for double liners and aleak detection, collection, and removalsystem or alternative design is sought asprovided by § 264.=(4d), (e), or -M- ofthis chapter, submit appropriateinformation;

(3) If the leak detection system islocated in a saturated zone, submitdetailed plans and an engineering reportexpiaining the leak detection systemdesign and operation, and -the locationof the saturated zone in relWion to teleak detection system

(4) The construction quality assurance(CQA) plan if required under 1 264.19 ofthis hapter;(S Proposed action leakage rate, with

ratimale, if required under I 204.2nofthis chapter, wd response action plan, ifrequired under § 264.223 of this chapter-

(c) A description of how each surfaceimpoundiet including the double linersystem, leak detection system coversystem and appurtenances forcontrdlof overtopping will be inspected inorder to meet the requiremet of§ 264.226(a. 4b), and 4d) of this chapter.This inf.mnaion mus e included in theinspection plan sub itted underI 270.14(b)(5):



.3496 Federal Register / Vol. 57, No. 19 / Wednesday, January 29, 1992 / Rules and Regulations

4. Section 270.18 is amended byrevising paragraphs (c) introductorytext, (c)(1) and (d) to read as follows:

§ 270.18 Specific Part B information forwaste plies.

(c) Detailed plans and an engineeringreport describing how the waste pile isdesigned and is or will be constructed,operated, and maintained to meet therequirements of § § 264.19, 264.251,264.252, and 264.253 of this chapter,addressing the following items:

(1)(i) The liner system (except for anexisting portion of a waste pile], if thewaste pile must meet the requirementsof § 264.251(a) of this chapter. If anexemption from the requirement for aliner is sought as provided by§ 264.251(b) of this chapter, submitdetailed plans, and engineering andhydrogeological reports, as appropriate,describing alternate designs andoperating practices that will, inconjunction with location aspects,prevent the migration of any hazardousconstituents into the ground water orsurface water at any future time;

(ii) The double liner and leak(leachate) detection, collection, andremoval system, if the waste pile mustmeet the requirements of § 264.251(c) ofthis chapter. If an exemption from therequircments for double liners and aleak detection, collection, and removalsystem or alternative design is sought asprovided by § 24.251(d), (e), or (f) ofthis chapter, submit appropriateinformation;

(iii) If the leak detection system islocated in a saturated zone, submitdetailed plans and an engineering reportexplaining the leak detection systemdesign and operation, and the locationof the saturated zone in relation to theleak detection system;

(iv) The construction qualityassurance (CQA) plan if required under§ 264.19 of this chapter;

(v) Proposed action leakage rate, withrationale, if required under § 264.252 ofthis chapter, and response action plan, ifrequired under § 264.253 of this chapter;

(d) A description of how each wastepile, including the double liner system,leachate collection and removal system,leak detection system, cover system,and appurtenances for control of run-onand run-off, will be inspected in order tomeet the requirements of § 264,254(a),(b), and (c) of this chapter. Thisinformation must be included in theinspection plan submitted under§ 270.14(b)(5);

5. Section 270.21 is amended byrevising paragraphs (b) introductorytext, [b)(1) and [c) to read as follows:

§ 270.21 Specific Part B Informationrequirements for landfills.

(b) Detailed plans and an engineeringreport describing how the landfill isdesigned and is or will be constructed,operated, and maintained to meet therequirements of § § 264.19, 264.301,264.302, and 264.303 of this chapter,addressing the following items:

(1)(i) The liner system (except for anexisting portion of a landfill), if thelandfill must meet the requirements of§ 264.301(a) of this chapter. If anexemption from the requirement for aliner is sought as provided by§ 264.301(b) of this chapter, submitdetailed plans, and engineering andhydrogeological reports, as appropriate,describing alternate designs andoperating practices that will, inconjunction with location aspects,prevent the migration of any hazardousconstituents into the ground water orsurface water at any future time;

(ii) The double liner and leak(leachate) detection, collection, andremoval system, if the landfill must meetthe requirements of § 264.301(c) of thischapter. If an exemption from therequirements for double liners and aleak detection, collection, and removalsystem or alternative design is sought asprovided by § 264.301(d), (e), or (f) ofthis chapter, submit appropriateinformation;

(iii) If the leak detection system islocated in a saturated zone, submitdetailed plans and an engineering reportexplaining the leak detection systemdesign and operation, and the locationof the saturated zone in relation to theleak detection system;

(iv) The consiruction qualityassurance (CQA) plan if required under§ 264.19 of this chapter

(v) Proposed action leakage rate, withrationale, if required under § 264.302 ofthis chapter, and response action plan, ifrequired under § 264.303 of this chapter;

(c) A description of how each landfill,including the double liner system,leachate collection and removal system,leak detection system, cover system,and appurtenances for control of run-onand run-off, will be inspected in order tomeet the requirements of § 264.303(a),(b), and (c) of this chapter. Thisinformation must be included in theinspection plan submitted under§ 270.14(b)(5);

6. Section 270.42 is amended byadding the following to Appendix I:

§ 270.42 Permit modification at therequest of the permittee.

Appendix I To i 270.42.-Classificaton ofPermit Modification

Modification Class

7. Construction quality assuranceplan:a. Changes that the CQA officer

certifies in the operatingrecord will provide equi'alentor better certainty that theunit components meet thedesign specifications ...................

b. Other changes ............................. . 2

H.6. Modifications of unconstructed

units to comply with§§ 264.221(c), 264.222, 2e4.223,and 264.226(d) ................. 1

7. Changes in response actionplan:a. Increase in action leakage

rate ....................... 3b. Change in a specific respone

reducing its frequency or ef-fectiveness ................. 3

c. Other changes ............................... 2

7. Modifications of unconstructedunits to comply with§§ 264.251(c), 264.252, 264.253,264.254(c), 264.301(c), 264.302,264.303(c), and 264.304 ....................

8. Changes in response actionplan:a. Increase in action leakage

rate ................................................. 3b. Change in a specific response

reducing its frequency or ef-fectiveness ................. 3

c. Other changes ............................... 2

PART 271-REQUIREMENTS FORAUTHORIZATION OF STATEHAZARDOUS WASTE PROGRAMS


Authority: 42 U.S.C. 6905, 6912(a), and 6926.

2. Section 271.1(j) is amended byadding the following entry to Table I inchronological order by date ofpublication:

§ 271.1 Purpose and scope.




TABLE 1. REGULATIONS IMPLEMENTING

THE HAZARDOUS AND SOLID WASTE

AMENDMENTS OF 1984

Promulga- Title of Federal Effectiveiomu dae Ril o Reister dttion date regulation refdeence

January Liners and 57FR (Insert July 29,29.1992. Leak FEDERAL 1992

Detection REGISTERfor PageHazard- Numbers]..ousWasteLandDisposalUnits z.

2 The following portions of this rule are not HSWAregulations: §§ 264.19 and 265.19 for final covers

[FR Doc. 92-1655 Filed 1-28-92; 8:45 am]

BILLING CODE 6N60-50M

3497

