Dear Mr. Aamodt:

5910 Northwood Drive Evergreen, CO 80439

www.ScientiaVeritas.com Healthcare: (303) 674-3732

Toxicology/Risk Assessment: (303) 67 4-8751 Facsimile: (303) 674-8755

Thank you for forwarding the two Blackwell documents entitled Third Five-Year Review Report. Soil Remediation Unit, Blackwell Zinc Site (May 2013) and Explanation of Significant Difference (May 2016), both of which were prepared by Blackwell Zinc, Inc. for the Oklahoma Department of Health (ODEQ) for my review and comment.

Blackwell Zinc, Inc. is an "RP" - a Responsible Party - in the administrative proceeding before the ODEQ. I understand that Blackwell Zinc, Inc. was purchased by other companies, and that these other companies include Freeport McMoRan , Inc. and Cypress Amax, Inc. I understand that the current Freeport McMoRan, Inc. companies are funding the studies in question in this letter. All of those companies are defendants in litigation where I have provided an expert declaration, and in which I have provided this letter . Therefore, I will refer to Blackwell Zinc, Inc. and the other companies, as the "RPs" for consistency.

I previously prepared a Declaration supporting the certification of a Class of Persons whose properties are contaminated by heavy metals - primarily lead, cadmium, arsenic and zinc. The heavy metals are the residue of an abandoned smelter. The heavy metals were spread in and around the town of Blackwell, Oklahoma. Dr. Fisher characterized the location of the heavy metals using data collected by the RPs. The RPs' data shows that lead, which is the subject of this letter, is only one of the heavy metals that causes a significant health threat to children and adults. The other heavy metals, particularly arsenic and cadmium present significant continuing health risks to the Class.

I reviewed both documents prepared by the RPs to determine whether the scientific risk assessment methodology the RPs used is correct and whether the updated soil cleanup level of 540 parts per million (ppm) of lead that the RPs propose is sufficiently adequate to protect the health of the Blackwell residents. Both of these documents present what the RPs call an "updated" analysis of the threat to human health posed by the lead in contaminated soil and lead resulting from historical site releases by the RPs into the community . Based on my review, the RPs' scientific risk assessment methodology of the threat caused by the lead released by the smelter is seriously flawed and outdated; consequently, the 540 ppm cleanup level for lead soil contamination falls far short of protecting the public. If the 540 ppm cleanup level is not reduced to approximately 150 ppm, there is a high probability that children and unborn fetuses will continue to suffer real, permanent, and irreversible damage to their rapidly developing brains. Additionally, the 540 ppm cleanup level continues to pose significant health threats to adults living in the Class Area.

My conclusion is based on a number of well-respected studies and scientific opinions as well as my independent analysis. First, in May 2012 Centers for Disease Control and Prevention (CDC) concluded that there is "no safe level of exposure to lead for children" ( available at http://www.cdc .gov/nceh/lead/acclpp/blood_lead_levels.htm), which has consensus agreement among all federal and state health agencies, and health professionals. Although there is no safe level of lead

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exposure, CDC in May 2012 set a practical goal of ensuring that children's blood levels do not exceed 5 micrograms per deciliter (5 µg/dL), which represents the 97 .5th percentile of the of the background population of children 1-5 years old in the United States. CDC refers to this as a "reference" level (prior to the 2012 update, CDC had used a blood level of 10 µg/dL as "level of concern"). Most notably among the health professionals who have adopted this updated reference level is the Oklahoma Department of Health (ODEH), which responded very quickly after CDC issued its report to update its Childhood Lead Surveillance program. In May 2012, ODEH lowered its reference blood level and began notifying parents with children, including parents in the Class Area whose blood level exceeded 5 µg/dL that the children have high levels of lead in their blood.

Likewise, essentially every public health professional in the United States, and most of them in the world have adopted the 5 µg/dL CDC reference standard. In contrast to the consensus of the community of nearly all U.S. public health professionals, the RPs' risk assessment continues to assume the previous reference of blood level of 10 µg/dl is safe (an incorrect assumption). While the "updated" risk assessment does incorporate new site-specific information regarding how residents are exposed, which resulted in a lowering of the "acceptable" lead soil level from 760 ppm to 540 ppm, it does not incorporate the updated CDC/ODEH reference blood level of 5 µg/dL-and it is this "update" that is the most important change that would have significantly lowered the cleanup level. It is unclear why the RPs' risk assessment relied on the old, outdated blood level 10 µg/dL since CDC lowered the reference blood level to 5 µg/dL a year before the third five-year review was issued and four years before the risk assessment was detailed in the RPs' Explanation of Significant Difference document.

Equally puzzling is the fact that the Third Five Year Review Report (2013) actually discusses the new CDC updated reference blood level value on page 5-3. Despite acknowledging the new CDC reference level of 5 µg/dL as the updated blood level that should be set as the goal to prevent brain damage in children, on page 5-3 the RPs make the following contradictory statement and instead illogically refers to a blood level of 10 µg/dL as being the standard:

The Remedial Action Objectives (RAO) for the SRU that is core to this ESD is:

• Prevent ingestion of lead in soil or dust originating from historical smelting operations at the Site that would result in a greater than five percent probability of an individual child or pregnant female having a blood lead concentration greater than 10 µgldL; [emphasis

added]

Setting the goal at 10 µg/dL (instead of 5 µg/dL) is what resulted in the soil lead cleanup level being 540 ppm, and this excessively high level will in tum result in many Blackwell children's blood lead levels exceeding the CDC's new reference level of 5 µg/dL. In fact, the Third Five Year Review Report (2013) actually presents a further discussion of the updated CDC and a table that shows the number of Blackwell children with blood levels already exceeding 5 µg/dL:

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Tbc risk C\'a.lwtion IqJOlt also comidem:I OSDH amiual moDi1oriog data for blood lead levels in the range of 5-9 µgtdL. In 2012. the CDC esmbli:sbed a new blood lead level reference value based on the 97~Sth perccatile in children fess than six yem old, whkh cur.rently equates to S pg/dL.

OSDH annual monitoring data for b1ood lead levels in the range of 5-9 µa,'dL is avai.W>le; b.owev«. die ~ ofbk:li.ld le.Ml Jevels io tlm ~ canrlOt be accum1ely determined because d:rt sampling methodorogy prior to July 2012 was de5ipcd to ~ blood lea(( ~ens at

10 µg/dL and gnmeT- Specifically, the 5-9 µgfdl. . l'3DF data were obtained \mJlg capillary

measurements that ~ oot confirmed by a veuo~ sampk Bl)d. lhus. are ~ u, the gn:al:CT

level of error inherent in 1be capillary sample collection method. Table 6 provides 1he OSDH

annual monitori.Dg d$. ba.s.ed oo oonve.nicnce sampling fur children in B1ackwdl with blood .lead revels at s p.gldl. OT higher . Similar ID the U'kw-grmttt pg.I'd!. data; the i-9 µg/dL data show a

do:reasmg trend

~!~~·,.!~~~~J'!!'4_'!!'-Jlll* -- -=-1 .. % ..roau- •illl~ •

· Yett , ~S~t. 2007

,.-.. ~i.-,-.--,.- ~ .-27.7%

. -·-

2008 13.4%

2009 22..9°.4

2010 18.8%

20U 9.5%

2012 6.5%

As I stated in my Declaration supporting the certification of a Class in this case, a health protective cleanup level for lead in soil corresponding to a blood level of 5 µg/dL is approximately 150 ppm. This is the same cleanup level that the RPs would have calculated if it had simply correctly adopted the CDC's updated blood level of 5 µg/dL, which they themselves identified as the correct updated CDC reference value.

The RPs used the EPA ' s standard Integrated Exposure Uptake Biokinetic Model (IEUBK) to determine what levels of lead the Class area soil should be remediated to. The IEUBK model is the same one I used. The most important assumption and input value when using that model is without question the CDC reference blood lead level for children. By setting the model to an acceptable blood lead level, the model then calculates the corresponding levels of lead in soil to determine the appropriate cleanup level. Only when the appropriate set point is used with the IEUBK model can toxicologists ensure that the CDC reference blood level is not exceeded. In contrast, when the IEUBK model is set at the outdated blood level of 10 µg/dL the result will correspond to an unsafe cleanup level for lead of 540 ppm. When one is true to the state of the science, and actually applies the CDC's updated standard of 5 µg/dL, the IEUBK result in Blackewell will be a cleanup standard of 150 ppm.

It is extremely disingenuous for the RPs to state a level of 5 µg/dL is the new CDC reference "safe" blood level, when they actually ran the IEUBK model set at the outdated level of 10 µg/dL.

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A 150 ppm clean up standard is consistent with the cleanup levels calculated and presented in numerous Superfund risk assessments prepared by the Agency for Toxic Substances and Disease Registry (A TSDR) since the 2012 CDC reference blood level was established. I specifically highlight the ATSDR health assessments because these are the only studies that are appropriate for an apple-to-apple comparison with the cleanup levels presented in the Blackwell risk assessment because: ( 1) they use the updated CDC reference level of 5 µg/dL and (2) they are solely based on science (rather than non-scientific criteria to the RPs apply).

ATSDR is responsible for all health assessments at Superfund sites. While it is often thought that U.S. EPA is responsible for the human health assessments at Superfund sites, it is actually ASTOR that has the sole responsibility for all public health assessments. Congress made this distinction of authority clear in the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). While Congress has charged U.S. EPA to lead the remedial investigation and clean-up efforts, it is A TSDR that has sole responsibility for conducting public health assessments to identify health risks. ATSDR summarizes these responsibilities on its website (available at http://blogs.cdc.gov/yourhealthyourenvironment/201 5/01 /27 /atsdr -investigates-superfund -sites/):

• In response to the environmental disasters at Love Canal and Times Beach, Missouri, Congress passed the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), commonly known as the Superfund legislation. CERCLA gave EPA primary responsibility for identifying, investigating, and cleaning up hazardous waste sites.

• CERCLA also authorized the establishment of ATSDR to assess the presence and nature of health hazards to communities living near Superfund sites, to help prevent or reduce harmfal exposures, and to expand the knowledge base about the health effects that result from exposure to hazardous substances.

• ATSDR was created as an agency under the Department of Health and Human Services on April 19, 1983. The Hazardous and Solid Waste Amendments of 1984 to the Resource Conservation and Recovery Act (RCRA) gave ATSDR additional authority related to hazardous waste storage facilities .

• ATSDR was charged with conducting public health assessments at these sites when requested by EPA, states, or individuals , as well as assisting EPA to determine which substances should be regulated and the levels at which chemicals may pose a threat to human health. ATSDR was formally organized as an agency on June 11, 1985. The Super.fund Amendments and Reauthorization Act of 1986 (SARA) broadened ATSDR's responsibilities in the areas of public health assessments, establishment and maintenance of toxicological databases, information dissemination, and medical education.[5] In 2003, the position of assistant administrator was replaced with a director who is shared with NCEH[J 3]

Furthermore, while U.S. EPA applies numerous non-scientific criter ia as part of its "nine NCP criteria" in determining appropriate cleanup levels (such as state and public acceptance and remediation costs) A TSDR conducts a health evaluation based solely on toxicology and epidemiology. Also, while ATSDR uses the most up-to-date, relevant, and appropriate scientific information to identify health threats , it can take U.S. EPA many years (sometimes more than a decade) to incorporate new toxicological information into its risk assessments . For example, U.S. while EPA has reached consensus that the updated CDC reference blood level is based on reasoned, sound and well-supported studies and recommendation, stating the following at a recent lead workshop (available at https://clu­in.org/meetings/leadinurbansoils/slides/Tuesday_091 Oa-Scozzafava.PDF):

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Lead and Health Effects

• 2013 National Toxicology Program Monograph on Health Effects of Low-level Lead­There is no threshold for adverse effects

• EPA 's 2013 Integrated Science Assessment - Cognitive function decrements in young children with mean blood Pb levels between 2 and 8 µgldL

• June 2012 Federal Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) to the CDC- blood lead "reference value" based on the 97.Sth percentile of blood lead levels in U.S. children aged 1-5 years (based on NHANES)

they have not acted with any urgency to incorporate this new information into their lead cleanup program which is supposed to, first and foremost protect children. EPA has yet to issue any regulatory guidance directing its toxicologists to update their risk assessment methodology and requiring them to use the 5 µg/dL reference level to set cleanup levels. More than four years after CDC's update, there is silence within U.S. EPA headquarters about updating its lead risk assessment methods and policy. Moreover, based on my recent discussions with U.S. EPA toxicologists, EPA Headquarters is unlikely to do so in the foreseeable future due largely to the cost of cleanup ( one of its nine NCP criteria) to the lower health protective level of 150 ppm. In contrast to U.S. EPA, ATSDR need not consider cost in its risk assessment. Accordingly, the A TSDR risk assessments and cleanup levels form the basis of comparison to the Blackwell risk assessment in this legal matter . That is, as a private litigation matter (rather than a regulatory action involving ODEQ) the sole issue at hand is whether the 540 ppm cleanup level is truly a health -based concentration . It is not.

Examples of where A TSDR has set the basis of its risk assessment and cleanup levels corresponding to CDC's 5 ug/dL blood level include the Former John T. Lewis and Brothers Site in Philadelphia. Another example is the public health assessment at the lead smelter site known as Caswell, Strauss and Co., where A TSDR used the IEUBK model set at 5 µg/dL to identify contaminated properties that pose unacceptable health risks from lead in children. At the Caswell Strauss site, ATSDR concluded that to protect children, the soil lead contaminant level should not exceed 154 mg/kg (mg/kg is in this case the same thing as ppm), which is approximately the same concentration I calculated (available at http://www .atsdr.cdc.gov/HAC/pha/Caswe11_Strauss_and_Co/Caswe11_Strauss_and_Co_LHC_2008-l32014.pdf).

In addition to making sure its risk assessments prevent children's blood lead levels from exceeding 5 µg/dL at lead contaminated sites, ATSDR has extended the science of lead risk assessments to analyze the impact of different soil lead cleanup levels to predict the outcome in terms of childhood blood levels (available at https ://clu -in.org/meetings/leadinurbansoils/slides/Tuesday 1400b-Wilder.PDF ). For example, ATSDR has shown that when the cleanup level is set at 100 ppm, the CDC reference level 5 µg/dL will not likely be exceeded. On the other hand, when the cleanup level is set at the (current) U.S. EPA default level of 400 ppm (which is even below the current Blackwell cleanup level of 540 ppm), there is a high probability of brain damage in children ages 6 months to about 5 years even when exposure to the site is limited to only 3 days per week.

As further evidence that the updated blood reference level is now well -established and accepted by all health professionals, ATSDR is currently in the process of updating its Lead Toxicity Profile document (which it is responsible for under CERCLA and is a one of the most widely used compendiums of toxicological information for all health professionals), stating:

"CDC has updated its recommendations on children's blood lead levels. Experts now use an upper reference level value of 97. 5% of the population distribution for children's blood lead. In 2012-2015 that value is 5 micrograms per deciliter (µgldL) to identify children with blood lead levels that are much higher than most children's levels. The information on this page refers to

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CDC's previous "blood lead level of concern of 10 µgldL. This information will be updated in future ToxProfile and ToxF A Q editions. To learn more about CDC's updated recommendations on children's blood lead levels, please visit: http://www.cdc .gov/nceMead/ACCLPP lblood lead levels.htm."

( available at https://www.atsdr.cdc.gov/phs/phs.asp?id=92&tid=22)

CDC has also just this year updated its definition of a lead "case" to correspond to 5 µg/dL. In epidemiology, a case definition is very important because it is used to identify the incidence of disease in the U.S. general population, as stated by CDC (available at https://wwwn.cdc .gov/nndss/case­definitions.html): .

A case definition is set of uniform criteria used to define a disease for public health surveillance . [ emphasis added]

As of 2016, CDC now includes all children and adults having a blood lead level of greater than 5 µg/dL (available at https ://wwwn .cdc.gov/nndss/conditions/lead -elevated-blood -levels/case-definition/20 l 6D as "cases" in its National Notifiable Diseases Surveillance System (NNDSS). The NNDSS is one of the primary sources that toxicologists and epidemiologists use to identify at-risk citizens:

The National Notifiable Diseases Surveillance System (NNDSS) is a nationwide collaboration that enables all levels of public health-local, state, territorial, federal, and international-to share notifiable disease-related health information . Public health uses this information to monitor, control, and prevent the occurrence and spread of state -reportable and nationally notifiable infectious and noninfectious diseases and conditions .

The new CDC case definition identifies any U.S. citizen (for both children and adults) having a blood lead level greater than 5 µg/dL as a disease "case" (available at https://wwwn.cdc.gov/nndss/conditions/lead -elevated -blood -levels/case -definition/2016/):

Laboratory Criteria for Diagnosis

Blood lead concentration on a venous blood specimen, as determined by a Clinical Laboratory Improvement Amendments (CLIA)-certifiedfacility, of~5 µgldL (0.24 µmo/IL) in an adult (person ~16 years of age).

In conclusion, for the reasons stated above, it is my opinion that the 540 ppm cleanup level for lead in soil derived by the RPs is likely to lead to real, significant, and irreversible brain damage in children in the Class area . The data collected by the ODEH shows that there are significant numbers of children still with very high blood lead levels in the Class Area. This is significant because in the prior class action, the Plaintiffs settled with the RPs for a cleanup standard of 500 ppm lead in the soil. While that cleanup appears from the data to be associated with lowering numbers of children that have high blood lead levels - who have "cases" - the number remains exceedingly high. As a result, the zip code that is essentially the Class Area continues to be listed by the ODEH as "High Risk Target Area" for high childhood blood lead levels. A map of those locations can be found on ODEH's website at https://www.ok.gov/health2 /documents /LEAD%20Map%20ofl/o20High%20Risk%20Target%20Area%2 0Zip%20Codes .pdf.

The science is clear - the cleanup level for lead in soil in the Class Area must be reduced to at least 150 ppm to meet the updated health criteria determined by CDC to be health protective for childhood and fetal lead exposures, as well as adults living in the Blackwell community .

Allegations by the RPs that lead in soil at a concentration of 540 ppm is safe for the residents in Blackwell is, in my opinion, irresponsible because it is likely to lead persons in the area to believe that they are safe to come in contact with soils that are actually quite dangerous . The RPs' allegation that the Oklahoma Department of Environmental Quality (ODEQ) has stated that 540 ppm lead is safe in soil is

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not accurate. Rather , as demonstrated above, the ODEQ relied on inaccurate assumptions that the RPs made while they recited the 5 ul/dl standard, even while disingenuously applying the old, higher IO ug/dl standard . Any person reading the RPs report that does not also know how to interpret the IUBEK model would also be misled as apparently the ODEQ was misled by the RPs' faulty risk analysis.

Sine~ . , __,.?t;,~·1t~~d~fr··· Richard DeGrandchamp , P . / . University of Colorado/S · ntia Veritas LLP

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