Environmental Issues Associated With Asphalt Shingle Recycling

Presented at the 3rd Asphalt Shingle Recycling ForumChicago, Illinois

November 1-2, 2007

• Jon T. Powell, E.I.• Innovative Waste Consulting Services• Gainesville, Florida

Project Background• Initial involvement to help develop

http://www.shinglerecycling.org• Compiled a white paper on behalf of CMRA and EPA that:

– Summarized two environmental questions/concerns raised regarding shingle recycling

– Collected data from recyclers in the US– Evaluated analytical data

• Published• Recycler-supplied

– Incorporated input from CMRA, EPA, UNH

• Will keep updating available analytical data as it is collected

Presentation Outline• Background• Overview of Asphalt Shingle Recycling• Environmental Questions or Issues

– Asbestos– Polycyclic Aromatic Hydrocarbons (PAHs)

• Conclusions• On-going research in Florida

Background• Asphalt shingles are the most common roofing

material in North America • Great market potential for recycling• Approximately 11 million tons of asphalt

shingle waste is generated per year– Post manufacture (scrap): 1 million tons– Post consumer (tear-off): 7-9 million tons

Typical Composition of An Asphalt Shingle

Base (fiberglass or organic felt)

Waterproofing asphalt

Waterproofing asphalt

Granular/aggregate

Back surfacing

Component Organic Felt Fiberglass Mat

Asphalt cement 30-36% 19-22%

Felt 2-15% 2-15%

Mineral granules/aggregate

20-38% 20-38%

Mineral filler/stabilizer 8-40% 8-40%

Asphalt Shingle Recycling

• Typical Management

Landfilling

Recycling

Asphalt Shingle Recycling• Markets

– hot mix asphalt (HMA)– temporary roads or driveways – dust control on rural roads – cold patch – aggregate road base – new shingles – Fuel/energy supplement– landfill cover– mulch

http://useit.umaine.edu/images/maingallery/msc9.jpg

Post-Consumer Asphalt Roofing Shingle Processing Facility

Raw Material

Asphalt shingles is droppedoff by roofing contractors.

Horizontal mill for size reduction

Trommel Screen

Overhead magnet used for the “under” and “over” streams

Unders – Used as HMA additive Overs – used as covering and paving material for unpaved roads

AsphaltShingles

Excavator

ShredderTrommelScreen

OverheadMagnet

FineASR

CoarseASR

Basic Layout of Post-ConsumerAsphalt Shingle

Processing Facility

Basic Layout of Post-ConsumerAsphalt Shingle

Processing Facility

FerrousMetal

OverheadMagnet

FerrousMetal

Environmental Concerns

ASBESTOS

PAHs

Possible Exposure Pathways

Grinding HMA Pavement, mulch, etc.

Release of Asbestos? PAH emissions?

PAH leaching?

or or

Health Impacts

• Asbestos– Lung cancer– Mesothelioma

• PAHs– Cataracts, kidney and liver damage– Some PAHs are identified as carcinogenic

Pathways of Possible Exposureat Recycling Operations

Generator Processing Facility(storage, grinding)

Most likely pathways of exposure

Pathways of Possible Exposurefor Recycling Operations

Generator Processing Facility(storage, grinding)

AsbestosAir Emissions

Water EmissionsPAH

Use in HMA

Direct Use

HumanContact

PAH

Regulatory pathways of concern

Water Emissions

PAH

Air EmissionsPAH

ASBESTOS

Types of Asbestos

• Chrysotile• Amosite• Crocidolite• Tremolite• Actinolite• Anthophyllite

Was Asbestos Widely Used?Manufacturer Years

Manufactured Product

Barber Asphalt Corporation NA Asphalt-asbestos roof felt

Carey Manufacturing Company NA Asphalt-asbestos shingles, asbestos finish felt, mastic

The Celotex Corporation 1906 through 1984 Asphalt roof coating and other miscellaneous materials

Fibreboard Corporation 1920 to 1968 Roof paint, roll roofings with asbestos-containing base sheets, caulking compounds, plastic cements, taping and finishing compounds

General Aniline and Film Corporation NA Roofing asphalt

Johns-Manville Corporation 1891 through 1983 Asphalt-asbestos shingles, rag-felt shingles, fibrous roof coating, shingle tab cement, roof putty

Kaylite Company NA Asbestos surface coating for shingles

National Gypsum Company 1941 through 1981 Roofing and shingles

Monroe Company NA Asbestos surface coatings for shingles

Rhone-Poulenc Ag Company Early 1930s through 1976 Adhesives, coatings, sealants, and mastics

United States Gypsum Company 1930 through 1977 Paper and felt

http://www.printedpages.net/ASBESTOS.html

Asbestos roof shingles (transite) were fairly common; however, this is not the same thing as asphalt shingles.

There were also a lot of other roofing products that used asbestos.

http://cgi.ebay.com/1913-JOHNS-MANVILLE-ASBESTOS-ROOFING-AD-LIKE-SOLID-ROCK_W0QQitemZ120168796596QQihZ002QQcategoryZ37831QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

“This roofing is made by crushing solid asbestos rock and compressing the long fibres into a dense, homogeneous felt. Several layers of this rock are then permanently cemented together with nature’s greatest water-proofer, Trinidad Lake Asphalt, making a light-weight roofing that is virtually a solid sheet of pliable stone.”

Asphalt Shingle Testing Results for Asbestos

• Data from processors in Maine, Iowa, Florida, Missouri, Minnesota, and Massachusetts

• Data available for 27,694 samples collected– 18 detections asbestos content <1%– 408 detections asbestos content >1%– Overall, asbestos detections in 426 samples

• Approximately 1.53%

Asbestos Summary• Asbestos was used in the manufacture of asphalt

shingles and asphalt-containing roofing materials in the late 1800s, continuing through to the 1980s.

• Asbestos phased out as component of asphalt shingles in the early 1980s.

• Data on asbestos content in asphalt shingles is very limited.

• Service life of an asphalt shingle is around two decades, +/-.

Asbestos Summary

• It is common practice in re-roofing to install new shingles directly on top of old ones. – As such, a load of post-consumer asphalt shingle waste

may contain multiple layers of asphalt shingles of varying age.

Asbestos Summary

• Analytical results of over 27,000 asphalt shingle samples indicated that about 1.5% of all samples detected asbestos.– Many asbestos detections were caused by other materials such as mastic that were attached to the samples.

http://cgi.ebay.com/1956-Insul-mastic-Co-Insulation-Catalog-Asbestos_W0QQitemZ330173307503QQihZ014QQcategoryZ4259QQcmdZViewItem

Asbestos Summary

• Despite the interference in the samples from the presence of mastic, the limited number of asbestos detections was consistent with the fact that asbestos was mostly phased out in the 1970s and that the typical reported service life for asphalt shingles is around 15-25 years, although effect of new shingles being installed on old ones may impact detection.

Asbestos Summary

• Obtaining/sourcing uncontaminated material should further reduce incidence of asbestos in samples– Some states restrict where the shingles can come

from

PAHs

• A group of over 100 different chemicals • Formed primarily during the incomplete burning

of coal, oil and gas• EPA identifies 7 PAHs as probable human

carcinogens – Benz(a)anthracene, Benzo(a)pyrene,

Benzo(b)fluoranthene, Benzo(k)fluoranthene, Chrysene, Dibenzo(a,h)anthracene, Indeno(1,2,3-cd)pyrene

What are Polycyclic Aromatic Hydrocarbons (PAHs)?

PAH Issues Raised

• Some have raised question of whether PAHs should be a concern when recycled asphalt shingles are:

• Ground up and used as road base• Ground up and used as mulch

– Leaching?– Direct Exposure?

• Used in HMA– Air emissions?

PAH Summary• Asphalt shingles naturally contain PAHs. • A leaching study on discarded asphalt shingles indicated

that PAHs did not readily leach PAHs. • Related studies on virgin roofing asphalt, reclaimed

asphalt pavement, and run-off from asphalt pavement indicated PAH concentrations below the laboratory detection limits. – However, since that study some acceptable levels have

decreased– Additional data are required to detect these samples at lower

concentrations

PAH Summary• PAHs are emitted during HMA production

– Pollution control equipment reduces PAH concentrations

• The effect of using post-consumer asphalt shingles in HMA on PAHs is unknown

• The use of post-manufacture asphalt shingles is permitted in some states

• A study in Texas investigating the issue of PAH emissions in HMA production has not yielded any data to date

PAH Summary

• It is not anticipated that clean, uncontaminated asphalt shingles would cause PAH emissions to be significantly different than virgin asphalt

Recommendations to State Regulators

• You can obtain a copy of our White paper, which provides recommendations for information and demonstrations a facility should make to recycle post-consumer asphalt shingles as part of permitting

RISK ASSESSMENT OF THE REUSE AND DISPOSAL OF SEVERAL ASPHALT WASTE MATERIALS

Ongoing Research

Overview

• University of Florida Department of Environmental Engineering Sciences– Solid and Hazardous Waste Laboratory

• Objectives:– Measurement of PAHs using instrumentation with

lower detection limits (shingles and RAP)– Risk-based analyses of PAHs and other chemicals

Polycyclic Aromatic Hydrocarbons (PAHs)

Parameter FL-GCTL (µg/L) Parameter FL-GCTL (µg/L)

Acenaphthene 20 Chrysene 5

Acenaphtylene 10 Dibenz[a,h]anthracene 7.5

Anthracene 2100 Fluoranthene 280

Benz[a]anthracene 4 Fluorine 280

Benzo[a]pyrene 0.2 Indeno[1,2,3-cd]pyrene 7.5

Benzo[b]fluorathene 4 Napthalene 6.8

Benzo[ghi]perylene 10 Phenanthrene 10

Benzo[k] 4 Pyrene 210

Leaching Test & Analysis in UF

Sample Collection (RAP & asphalt shingles)

Leaching Test (SPLP + TCLP)

Analysis leaching solution

PAH AnalysisHeavy metals and other analyses

Acknowledgments

• CMRA and EPA• UNH• Facilities that provided data

Thank You

Jon Powell, E.I.Innovative Waste Consulting Services6628 NW 9th Blvd, Suite 3Gainesville, Florida 32605352-331-4828 Extension 4jpowell@iwcs.bizhttp://www.iwcs.biz

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