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BoRit Questions & Answers -Ambler Asbestos Superfund Site

BoRit Questions & Answers Main Page
  1. What course of action did EPA follow to mitigate asbestos from the Ambler Asbestos site? (7-3-2010)

  2. Why did EPA choose an on site containment remedy for the Ambler Asbestos site? (7-3-2010)

  3. Is the Ambler Asbestos Site in violation of Pennsylvania’s landfill requirements due to the deep rooted vegetation, permeable barriers, and slopes greater than 33 degrees?
    (7-3-2010)


  4. Is the Ambler Asbestos site in violation of the Clean Water Act (CWA)? (7-3-2010)

  5. Does EPA monitor the ambient air for asbestos contamination as part of the cleanup at the Ambler Asbestos site? (7-3-2010)

  6. Is EPA governing the Ambler Asbestos using the National Emission Standard for Hazardous Air Pollutants (NESHAPs) law and the Clean Air Act (CAA) and Clean Water Act (CWA)? (7-3-2010)

  7. The site was covered with soil and vegetated in the past, yet the asbestos waste became uncovered. Can EPA explain why this has occurred and is it unsafe? (7-3-2010)

  8. Could animal and other natural disturbances to the Ambler Asbestos piles cause asbestos to come through a soil cap? If so, how will EPA mitigate these animal and natural disturbances to the soil cover? (7-3-2010)

  9. Did EPA and Agency for Toxic Substances and Disease Registry (ATSDR) assess all possible risks to human health from asbestos and communicate those risks to the public? (7-3-2010)

  10. Will EPA consider performing a soil and air analysis for asbestos on the Ambler Asbestos Pile? (7-3-2010)

  11. How much money has been spent to date by the EPA for Ambler Asbestos Piles Superfund Site? (7-3-2010)

  12. Why did EPA have to conduct maintenance work at the site and is the revetment failing? (7-2010)

  13. Has there been a release of asbestos and other toxins into the Wissahickon creek because of the stream erosion around the revetment? (7-2010)

  14. Is the placement of rocks a good remedy for the repair? (7-2010)

  15. What is the life expectancy for the concrete revetment? (7-2010)

  16. Is the remedy for the Ambler Asbestos site protective of human health and the environment and why they decided to do the maintenance work? Can EPA explain why asbestos has been detected in the creek near the site? (7-2010)

  17. Will EPA hold a public meeting to tell the community about the repair work? (7-2010)

  18. Has EPA evaluated the effectiveness of the cleanup of the Ambler Asbestos piles?
    (6-2-2010)


  19. Are the trees/vegetation on the Ambler Asbestos site impacting the effectiveness of the protective cap? (4-20-2009)

  20. Why did EPA issue an Explanation of Significant Differences (ESD) for the Ambler Asbestos Superfund Site and will the ESD impact future reuse? (4-20-2009)

  21. What technology/techniques were used to remediate the Ambler Asbestos Piles National Priorities List site and would they be used at BoRit and how would they be applied? (1-2008)

  22. What are the primary differences between how EPA is handling the asbestos contamination at BoRit, compared to what was done at the Ambler Asbestos Superfund Site, and the Libby Montana Site? (3-12-2007)

  23. How is EPA handling the asbestos contamination at BoRit, compared to what was done at the Ambler Asbestos Superfund Site, and the Libby Montana Site? (1-24-07)

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  1. What course of action did EPA follow to mitigate asbestos from the Ambler Asbestos site? (7-3-2010)

    During the 1980s, EPA's Superfund program responded to the asbestos contamination in Ambler by conducting removal response actions and a full investigation into the major sources of asbestos. The results of this investigation are documented in the Remedial Investigation and Feasibility Study reports for the Ambler Asbestos Piles Superfund Site. Ultimately, the massive uncovered waste piles with exposed asbestos containing waste (the Locust Street Pile and the Plant Pile) were addressed as the Ambler Asbestos Piles Superfund Site, which also included the immediately adjacent CertainTeed Pile and the former settling lagoons. This Site was remediated in accordance with the remedies selected and documented in the two Records of Decision for the Site. The Maple Avenue Piles were already covered and vegetated, and monitored by the Pennsylvania Department of Environmental Resources, and at the time, EPA determined they did not warrant Superfund action.

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  2. Why did EPA choose an on site containment remedy for the Ambler Asbestos site? (7-3-2010)

    The selection of the remedy was based on commonly accepted, existing soil principles, combined with the regulations specific to asbestos that were and are still applicable. The capping systems implemented at the Ambler Asbestos Piles Site utilized soil and vegetative cover for the steep side slopes with engineered multilayer caps for the flat plateaus of the Locust Street and Plant Piles. The CertainTeed Pile was capped with soil and vegetation only. All parts of the containment remedy for the Ambler Asbestos Piles Site comply with the requirements of the National Emission Standards for Hazardous Air Pollutants (NESHAPs), which are the regulations that EPA uses regarding abandoned asbestos factories and disposal sites. The NESHAP regulations for asbestos are contained in 40 CFR 61.140 through 61.157. Further information on EPA's regulations concerning asbestos is available on the EPA website at: http://www2.epa.gov/asbestos

    The basic principles supporting soil as an appropriate cover for asbestos containing waste are summarized here. Asbestos is a generic term used to describe a group of fibrous silicate minerals that occur naturally in the environment and have been mined for commercial use. The asbestos minerals have high tensile strength, the ability to be woven, and resistance to heat and most chemicals. Because of these properties, asbestos fibers have been used in a wide range of heat resistant, durable manufactured goods.

    The physical properties of asbestos are also the reason that asbestos is not expected to move through soil. It is a mineral (i.e., rock) and dense, having a specific gravity typically reported as ranging between 2.0 and 3.5 (two to three and a half times heavier than water), depending on the mineral variety. Asbestos is made up of fibers, and although the fibers and fiber fragments can be microscopic, these particles are still large, complex molecules in the microscopic environment. The fibers are not soluble and, therefore, cannot be transported in a water solution like other, smaller contaminant molecules and ionic species. The particles are also too large to be transported preferentially by other physical-chemical processes like diffusion. Therefore, asbestos fibers tend to remain stationary within the soil matrix. In other words, in a natural soil setting, asbestos fibers do not move through the soil.

    An analysis published by EPA in April 1977, Movement of Selected Metals, Asbestos, and Cyanide in Soil: Applications to Waste Disposal Problems, EPA Publication Number EPA-600/2-77-020, describes the potential for asbestos movement through soil. Although the author, Dr. Wallace H. Fuller, recognizes the paucity of data specific to asbestos, he argues that asbestos is reasonably expected to behave like similarly sized clay particles, which have been extensively studied. 

    "Although there are no data on mobility of asbestos in soil, predictions about its behavior can be made with reasonable confidence. Since the weathering products of asbestos are the common nonhazardous salts of Ca, Mg, and Si, physical transport is the only mode of movement in soil which is of significance. The extensive data on movement of clay­ sized (<2µ diameter) particles by strictly physical processes provide a convenient yardstick for gaging the probable behavior of asbestos in soil. Clay particles 0.1 to 2.0µ in diameter are estimated to move at a rate of 1 to 10 cm per 3,000 to 40,000 years, depending on the soil texture (Berkland, 1974). There is no reason to expect that asbestos particles of similar size would move differently from this. Consequently, asbestos migration through soil will not be a problem of any significance."

    It can be added that larger particles (i.e. the longer fibers of the asbestiform minerals) are expected to be even more resistant to movement due to physical impedance.

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  3. Is the Ambler Asbestos Site in violation of Pennsylvania’s landfill requirements due to the deep rooted vegetation, permeable barriers, and slopes greater than 33 degrees?
    (7-3-2010)

    The Ambler site is not in violation of Pennsylvania law.  Deep-rooted vegetation is not allowed on most landfill covers because of the potential for damage to underlying geosynthetic membranes that are a typical component of caps. Because the contaminant of concern is asbestos, the side slopes of the Locust Street and Plant Piles were covered with soil and vegetation and do not have geosynthetic membranes, and removal of deep-rooted vegetation (i.e., trees) was not required. Additionally, the presence of trees on the side slopes of these piles is considered beneficial. Tree roots add structure and strength to loose soil components to make them more slide-resistant. Tree roots also absorb excess moisture that could otherwise build up in the soil turning it into unstable mud (for an extreme example, reference the mud slides of California). Tree roots at the Ambler Asbestos Piles Site are also expected to be deep enough to be anchored into the underlying cinder berms that constitute the constructed walls of the original disposal areas. Being anchored into a more structurally stable sub-layer gives the roots additional strength to hold the soil.

    On the level plateaus atop the Locust Street and Plant Piles, engineered capping systems were designed and constructed. These cap systems included semi-permeable barriers. This is a departure from the impermeable barriers for cap systems and bottom liners that are typically required by the hazardous waste landfill, residual waste landfill and municipal waste landfill regulations. These regulations were developed for landfills containing putrescible and other types of waste that are expected to generate toxic gases and leachate that could contaminate underlying soils and/or groundwater. An impermeable cap serves to contain the waste, prevent gases from escaping and prevent rain water from percolating through the cap into the waste, thereby increasing the leachate volume. (Less water leaking in through the top leads to less leachate volume in the fill.)

    The purpose of the cap systems for the Locust Street and Plant Piles of the Ambler Asbestos Piles Site is markedly different from those typically required for hazardous or municipal landfills. Because the waste at the Site is predominantly a wet plaster-like substance, EPA does not expect and is, therefore, not concerned about gas and leachate production. The cap system was specifically designed for containment of this waste, with drainage features to carry off most of the water from precipitation, and a semi-permeable membrane on the top plateaus to allow some moisture to infiltrate through the waste to maintain its wet plaster-like consistency. To prevent damage to the semi-permeable membrane and the drainage features, the Record of Decision required the removal of trees and other vegetation and the continued prevention of re-emergence of vegetation on the top plateaus.

    There are no liners or membranes on the side slopes because the remedy did not need to completely prevent water infiltration (and most of the water runs off the slopes naturally). This is a significant departure from most landfills, but is appropriate to the characteristics of the Ambler Asbestos Piles Site. There is no concern that deep tree roots will compromise membranes on the side slopes because there are not any such membranes. And, as explained above, the trees were allowed to remain on the forested side slopes because the root systems of the trees are expected to have a stabilizing effect on the soil of the very steep slopes.
     
    The rationale for allowing slopes steeper than 33 degrees (3:1 slope) at the Locust Street and Plant Piles of the Site is detailed in the Remedial Investigation/Feasibility Study (RI/FS) documents for the Site and summarized here. The Locust Street and Plant Piles were originally created by building containment berms of piled cinders (cinder berms), and then pumping in waste slurries and allowing the waste to set. Some of the waste infiltrated the cinder berms, drying and acting, to some extent, as a binder. Consequently, the slopes, which are now covered with soil and vegetation, are steep but have proven to be stable structures. Attempting to restructure the slopes to be less severe would necessitate removal, or partial removal, of the cinder berms. As described in the RI/FS, "Reduction in the thickness or removal of these berms may cause a collapse of the piles and a release of calcium/magnesium carbonate and asbestos materials ..."

    Another method for achieving a flatter slope would involve adding material to the bases of the existing slopes. However, due to the limited space surrounding the Site, regrading or adding material to ease the slopes would necessitate expanding the base footprint of the Site. As discussed in the RI/FS, "In order to establish 3:1 or flatter slopes on all of the piles side slopes, potential encroachment to near the commuter rail line, onto the residential areas north and west of the Locust Street Pile, into the flood plain, and into a portion of the Wissahickon would result."

    Because of the structural stability of the existing slopes, the infeasibility of reducing the steepness and other considerations, EPA selected the On-Site Closure Remedy for the Ambler Asbestos Piles Site, waiving the slope requirements of Pennsylvania Municipal Waste Regulations at 25 PA 273.234.

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  4. Is the Ambler Asbestos site in violation of the Clean Water Act (CWA)? (7-3-2010)

    The Ambler Asbestos Site is not in violation of the CWA. During the Remedial Investigation/Feasibility Study (RI/FS), the potential for discharge of asbestos to the groundwater at the Ambler Asbestos Piles Site was determined to be minimal and, therefore, no preventive actions were required. As discussed in the RI/FSdocuments, because of the physical characteristics of asbestos, it is not mobile in soil and discharge to groundwater is not expected. The RI/FSfor the Ambler Asbestos Piles Site states, "Ground water is not expected to be a significant migration pathway for asbestos at this site. This is due to two factors: 1) the site's location in a hydrologic discharge zone where generally base- flow is slightly upward and toward the stream; and 2) the relative insignificant subsurface downward or lateral migration of asbestos fibers in soils. To date, there is no documentation of groundwater transport of asbestos particles (Dalton, U.S. EPA, 1985)."

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  5. Does EPA monitor the ambient air for asbestos contamination as part of the cleanup at the Ambler Asbestos site? (7-3-2010)

    Consistent with the relevant regulations for asbestos disposal sites under the National Emission Standard for Hazardous Air Pollutants (NESHAPs), ambient air sampling was not required.
    On August 30, 1993, following the completion of construction at the Ambler Asbestos Piles Site, EPA issued a Final Close-Out Report certifying that the remedy was completed in accordance with the Record of Decisions. The containment remedy for the Ambler Asbestos Piles Site was designed to significantly reduce the potential for release of asbestos fibers to the environment.

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  6. Is EPA governing the Ambler Asbestos using the National Emission Standard for Hazardous Air Pollutants (NESHAPs) law and the Clean Air Act (CAA) and Clean Water Act (CWA)? (7-3-2010)

    EPA is addressing the site under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) authority. Under CERCLA, any selected remedy must be protective of human health and the environment and in compliance with Applicable or Relevant and Appropriate Requirements, which may include the CAA and CWA. The NESHAPs are regulations established under the federal CAA that specifically relate to asbestos and other contaminants that have been identified as 'hazardous air pollutants.' Under Section 112(d) (6) of the CAA, EPA is required to review standards issued under Section 112 and to revise them "as necessary (taking into account developments in practices, processes and control technologies)."

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  7. The site was covered with soil and vegetated in the past, yet the asbestos waste became uncovered. Can EPA explain why this has occurred and is it unsafe? (7-3-2010)

    At the Ambler Asbestos Piles Site, there are pieces of apparently discarded asbestos products visible on the side slopes of the piles. These discarded pieces are few in number and have remained on the piles, undisturbed, for years. There is no indication that these pieces were ever covered, but because they are durable goods, asbestos cement pipes and asbestos wall board, they are not expected to be friable or likely to release asbestos, and were not removed.

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  8. Could animal and other natural disturbances to the Ambler Asbestos piles cause asbestos to come through a soil cap? If so, how will EPA mitigate these animal and natural disturbances to the soil cover? (7-3-2010)

    For the Ambler Asbestos Piles Site, two Operation and Maintenance Plans (O&M Plans) are currently being implemented by the current owner and the Responsible Parties who constructed the original remedies. The O&M Plans require routine inspections of the Site, maintenance of the fencing and necessary repair of damage to the cover systems caused by trespassers, burrowing animals, fallen trees, erosion, or other causes. Animal burrows have been observed on the side slopes with extracted soil and potential waste materials surrounding the burrows. In accordance with the O&M Plans, the disturbed soil and materials are gathered back into the burrow holes and tamped down.

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  9. Did EPA and Agency for Toxic Substances and Disease Registry (ATSDR) assess all possible risks to human health from asbestos and communicate those risks to the public? (7-3-2010)

    The goal was and continues to be to address highest priority threats for exposure to the community first. The long timeline involved and the extent of the asbestos contamination in the Ambler area resulted in a complex matrix of agency responses over the decades. Based on the available relevant environmental authorities, distinct aspects of the contamination concerns were separated out for different oversight actions.

    The Center for Disease Control/ATSDRand the Pennsylvania Department of Health have evaluated exposure information, reviewed health outcome (e.g., cancer data) information, and provided health opinions for the asbestos contamination in the Ambler area since the 1970s. The health agencies have issued public health warnings about the contamination in the area, including a Public Health Advisory focusing on the Ambler Asbestos Piles National Priorities List Site area in 1983. Starting in the 1980s and continuing currently, the environmental and health agencies have reviewed environmental sampling data as it becomes available and have made and continue to make recommendations to fill identified data gaps. As new environmental sampling data has become available and mitigation actions have been implemented, the health agencies have revised and updated the public health conclusions and recommendations for the community accordingly.

    Contamination in and around Wissahickon Creek has been known to the agencies and is an ongoing indicator of the history of disposal activities affecting the community. The current environmental sampling data for sediments and streams in the site area (Wissahickon Creek, Rose Valley, and Tannery Run) do not indicate that recreational contacts with these streams/sediments would be a problem based on the transient levels of exposure recreational users would experience in these wet environments. EPA's 2006-2007 environmental sampling data support this conclusion regarding the streams and sediments; this air data indicates that people offsite are not inhaling asbestos at levels of health concern. Additionally, based on water and sediment sample results, people are not being exposed to asbestos at levels of health concern from contacting the surface water and generally playing, walking, and fishing in the creeks. However, EPA is currently in the process of collecting additional environmental sampling data relevant for further evaluation of recreational activities in and around the Wissahickon Creek. The agencies will use this information to further revise our understanding of this exposure pathway and will update the findings for the community accordingly. 

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  10. Will EPA consider performing a soil and air analysis for asbestos on the Ambler Asbestos Pile? (7-3-2010)

    As part of a current investigation of the former Keasbey and Mattison buildings, air samples for asbestos analysis are planned for areas at the perimeter of the Ambler Asbestos Piles Site. These samples are to be used to help determine the ambient background for the area. If high levels of asbestos are present in the samples near the Ambler Asbestos Piles Site, EPA will consider performing further sampling as necessary. Additionally, EPA will reevaluate the Ambler Asbestos Piles Site with regard to soil and air analysis as part of its Five-Year Review process.

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  11. How much money has been spent to date by the EPA for Ambler Asbestos Piles Superfund Site? (7-3-2010)

    Ambler Asbestos/CertainTeed Operable Unit 1/Operable Unit 2 Combined EPA Costs Incurred for the Ambler Asbestos Piles Site, Pennsylvania
    Total Site Costs through May 2010:  $5,387,017.13
    Total Costs Recovered:  $1,667,438.90

    FY 2006 Total Costs:  $12,692.39
    FY 2007 Total Costs:  $18,020.01
    FY 2008 Total Costs:  $ 7,928.29
    FY 2009 Total Costs:  $61,178.87
    FY 2010 Total Costs through May, 2010: $42,889.72

    It is important to note that EPA's costs to date do not include the actual costs of constructing the main remedies or conducting the long-term Operation and Maintenance (O&M) at the Ambler Asbestos Piles Superfund Site. These costs were expended by the responsible parties that constructed the remedies for the Site pursuant to agreements with EPA. EPA does not know how much the parties spent, but the original estimate of capital and maintenance costs for the Site was $6,942,000.

    Because the Potentially Responsible Parties have agreed to conduct the O&M (which includes inspection and repairs) of the Ambler Asbestos Piles Site, EPA's future costs are expected to be minimal and no specific allocations have been set aside for this Site.

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  12. Why did EPA have to conduct maintenance work at the site and is the revetment failing? (7-2010)

    EPA evaluated the effectiveness of the cleanup and the need for routine maintenance and repair.  Our evaluation determined that the cleanup continues to be protective of human health and the environment.  This evaluation also determined that the revetment has not failed, but is in excellent condition.  EPA did determine, however, that the stream bank is eroding around the concrete revetment and needs to be stabilized to preserve the integrity of the revetment.  By making these repairs to the stream bank, EPA expects the revetment to stay in place for decades to come.

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  13. Has there been a release of asbestos and other toxins into the Wissahickon creek because of the stream erosion around the revetment? (7-2010)

    The erosion of the stream bank around the concrete revetment did not contribute to a release of asbestos or other toxins from the Ambler piles.  Because the erosion is occurring upstream of the concrete revetment and along the lower edge of the revetment beyond the extent of the Ambler Asbestos piles, it is the native soils and sediments of the stream bank that were washed away by water of the Wissahickon.

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  14. Is the placement of rocks a good remedy for the repair? (7-2010)

    EPA is using an established technology to stabilize the stream bank, called riprap.  Riprap is a universally accepted and recommended method in civil engineering for this type of erosion control.  The work will include reinforcing the stream banks with large angular stone (riprap).  The installation of properly sized rocks will rival the strength and stability of the concrete revetment. 

    - For anyone interested in knowing more about the effectiveness of riprap, the following link provides a good, plain language fact sheet on riprap for stream erosion.
    http://www.dnr.state.oh.us/water/pubs/fs_st/stfs16/tabid/4171/Default.aspx

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  15. What is the life expectancy for the concrete revetment? (7-2010)

    The revetment has been in place for 17 years, and is in excellent condition.  The maintenance work will ensure that it continues to be effective for decades to come.

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  16. Is the remedy for the Ambler Asbestos site protective of human health and the environment and why they decided to do the maintenance work? Can EPA explain why asbestos has been detected in the creek near the site? (7-2010)

    EPA has certified in three consecutive Five Year Reviews that the remedy implemented at the Ambler Asbestos Piles Superfund Site is in good condition and continues to be protective of human health and the environment.  EPA expected repairs would have to be made over time, and we planned for that in our Operation and Maintenance (O&M) program.

    As a result of the long-term O&M activities and, as reported in the last Five Year Review, EPA became aware of erosion of the stream bank at the upstream edge and along the toe (down slope edge) of the concrete revetment.  The consultant responsible for O&M on the Locust Street Pile began planning the maintenance activities for the revetment in 2007.  EPA and the Pennsylvania Department of Environmental Protection (PADEP) approved the repair design in December 2008, and the maintenance is now being implemented in August 2010.  The contractor for the work shared the plans and schedule with the Ambler Borough Manager, Wissahickon Valley Water Association, the Montgomery County Conservation District and PADEP.

    EPA believes that the suspected asbestos containing materials (pipe and shingle fragments) have been carried down from other, upstream sources by the water flow in the Wissahickon.  Similar materials are evident upstream of the Ambler Asbestos Site location.

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  17. Will EPA hold a public meeting to tell the community about the repair work? (7-2010)

    At this time, EPA does not plan to hold a public meeting about the Ambler Asbestos maintenance work.  However, we are happy to respond to questions from the community. In addition, we can offer to update the community on the maintenance work at an upcoming CAG meeting, which , like all CAG meetings, will be open to the public.  Also, as part of our ongoing work at the BoRit Asbestos Site, EPA plans to host a series of open houses and public meeting opportunities and we would be happy to address any questions or concerns regarding the Ambler Asbestos Site during those meetings.

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  18. Has EPA evaluated the effectiveness of the cleanup of the Ambler Asbestos piles?
    (6-2-2010)

    Since the cap remedy for the Ambler Asbestos Piles was completed in 1993, EPA has continued to monitor the conditions of the Site and the ongoing maintenance programs being conducted at the Site by the Potentially Responsible Parties. The Site is inspected on an annual basis and Five-Year Reviews are conducted. As a result of these inspections, typical maintenance issues are identified and addressed. The stone covered pile plateaus have remained level, with even coverage and almost no settling. The side slopes, stabilized by the roots of the mature trees, show very little erosion. The small disturbances in the soil cover used by burrowing animals have been and will continue to be repaired as part of the maintenance programs.
     
    The erosion control devices are in excellent condition and continue to protect the piles against the scouring action of the Wissahickon and Stewart Farm Creeks. Some native soils have been washed away from the upstream end of the Wissahickon device (the revetment) and two small areas on the stream side of that device, but not to the point of threatening the pile or impacting the effectiveness of the device. As part of the regular maintenance programs, repairs to address those undermined areas are scheduled for 2010; the designs have been approved and permits are being obtained. The security fences surrounding the Site are periodically cut by vandals and trespassers, but are repaired under the maintenance programs. In consideration of the observed physical conditions and the ongoing maintenance activities, EPA has certified the protectiveness of the Site in three consecutive Five-Year Reviews of the Remedy at the Ambler Asbestos Piles Superfund Site.

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  19. Are the trees/vegetation on the Ambler Asbestos site impacting the effectiveness of the protective cap? (4-20-2009)

    The cap on the Ambler Asbestos Superfund Site is not failing. In fact, we know that the cleanup is succeeding because the third Five-Year Review for the site, conducted in 2007, documents that the cleanup continues to be protective of human health and the environment. The trees on the side slope were allowed to remain there because their root systems provide the stabilization for the very steep slopes.

    In addition, EPA has an operation and maintenance program in place to inspect and repair any damage or erosion to make sure that the cleanup remains protective of human health and the environment.

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  20. Why did EPA issue an Explanation of Significant Differences (ESD) for the Ambler Asbestos Superfund Site and will the ESD impact future reuse? (4-20-2009)

    The ESD for the Ambler Asbestos site is a required fulfillment of the Superfund law and not an attempt by the EPA to prevent site reuse. The Record of Decision is the legal document which directs how EPA will clean up a site. The institutional controls (ICs) are the restrictions that EPA puts on the site to ensure that any future use of the site does not compromise the cleanup and remains protective of human health and the environment.

    To clarify, a form of ICs, the requirements of the operation and maintenance program, has been in place since the remedy was constructed. It is now EPA policy to legally require ICs. To comply with the law, an ESD is required to officially document the ICs. Again, it is important to note that EPA has been following the requirements of the operation and maintenance program since the remedy was constructed, and will continue to do so, to ensure that the cleanup remains protective of human health and the environment.

    Officially documenting the ICs through an ESD further ensures that - whatever future uses may be chosen for the site - remain protective of human health and the environment.

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  21. What technology/techniques were used to remediate the Ambler Asbestos Piles National Priorities List site and would they be used at BoRit and how would they be applied? (1-2008)

    The Ambler Asbestos Piles Site was remediated by capping, covering and vegetating the site. The technology for asbestos removal remains basically the same. Although other remedies have been proposed, (removing the materials, etc.) they are extremely cost prohibitive and would require moving asbestos-containing material through other communities to reach an approved dump site.

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  22. What are the primary differences between how EPA is handling the asbestos contamination at BoRit, compared to what was done at the Ambler Asbestos Superfund Site, and the Libby Montana Site? (3-12-2007)

    The Libby, Ambler Asbestos, and BoRit Sites are distinct sites differing from each other in several ways. Each site has its own set of unique circumstances and environmental conditions that require independent evaluation by the Agency for Toxic Substances and Disease Registry (ATSDR) and EPA. Some of the significant differences include meteorological conditions (i.e., the amount of precipitation at each site - Libby, MT vs. Ambler, PA), the different mineral types of asbestos, the vegetation and ground cover, and the matrix in which the asbestos is contained. These variables all affect how much asbestos people have been or are exposed to. All of these variables influence EPA's decision-making at each site. The following outlines some of the most obvious differences between the sites:

    In Libby, people were exposed to asbestos at relatively high levels through numerous exposure pathways. There was an active mine on the edge of town that brought raw material into the town for processing and shipping. Workers were exposed at the mine, at the processing plants, and at areas in town that were contaminated. Limited data suggest the asbestos air levels in town may have reached today's occupational exposure limits (i.e., 0.1 f/cc). Within Libby there were piles of material people played on, the high school track was made from contaminated material, and the material was used in gardens and as house insulation.

    In Libby, vermiculite was mined. The vermiculite was contaminated with a type of asbestos called amphibole, a mineralogical term for a group of minerals that have similar chemistry. Most toxicologists think amphibole asbestos is more toxic, especially at producing mesothelioma, than the more common asbestos type, chrysotile.

    At BoRit, EPA air sampling data to date does not show a significant airborne concentration of asbestos at the Site. To further refine our understanding of that data and to help better make decisions specific for BoRit, EPA along with ATSDR, is conducting more air sampling, including activity-based sampling at the Site. This type of sampling will give the federal agencies an understanding of the worst-case air levels that can result from the materials at BoRit in its current condition.

    The type of asbestos at BoRit found thus far is primarily chrysotile. Chrysotile can cause the same diseases seen in Libby, but most toxicologists think chrysotile is much less likely to cause mesothelioma than is amphibole, the type of asbestos in Libby. In addition, the process at BoRit involved combining asbestos into a product that binds the asbestos. This helps limit the amount of asbestos that can be re-entrained into the air. This does not mean that chrysotile asbestos is not toxic or that the AsbestosContaining Material cannot release fibers. It simply means that the risk of being exposed to BoRit asbestos and becoming sick is much less than with materials such as those found at Libby.

    The Libby and Ambler Sites each went through an investigatory process similar to the one that the BoRit Site is now undergoing. Libby and Ambler both were listed on the National Priorities List (NPL) as Superfund Sites, based on EPA's hazard ranking system. BoRit is still being investigated and may or may not reach NPL status.

    At the Ambler Site, although the type of asbestos material appears to have been similar to the type found at BoRit (generally chrysotile versus amphibole), the risk of exposure at Ambler was found to present an immediate threat to the public, based on findings by the ATSDR and the Pennsylvania Department of Health (PADOH). The exposure risks at the Ambler Site were likely higher due to the manufacturing activity, the uncovered state of certain of the Ambler piles, and the public's access to and actual contact with those piles. At BoRit, based on the ambient air sampling results from October and November 2006 residents in the vicinity of the BoRit Site are not being exposed to asbestos fibers from the Site at levels that pose an unacceptable or significant health risk.

    The size of a particular site is not the primary factor in EPA’s decision-making, it is the risk posed. EPA will respond to an immediate threat to public health and environment regardless of the size of a site.

    There is no single solution for every site that has asbestos contamination. The solution to the asbestos problem in BoRit must be based upon the unique findings at BoRit.

    For more information about the Ambler Asbestos Superfund Site, go to http://www.epa.gov/superfund/sites/npl/nar322.htm http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0300445

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  23. How is EPA handling the asbestos contamination at BoRit, compared to what was done at the Ambler Asbestos Superfund Site, and the Libby Montana Site? (1-24-07)

    The Ambler Asbestos National Priorities List (NPL) Site consists of the Locust Street Pile, Plant Pile and Pipe Plant Dump. Based on area dimensions from viewing aerial photographs, it appears roughly similar in size to the BoRit Site, which consists of the BoRit Pile, Reservoir and Whitpain Park. However, the waste depths and volumes of waste contained within these individual sub-sites can only be estimated. Our Remedial Program will have the best information for the Ambler Asbestos Site.

    Regarding our ''treatment'' of the BoRit Site in comparison to the Ambler Asbestos Site, size is not a primary determining factor. We have routinely addressed smaller unrelated sites in an emergency manner due to the nature of the hazard (e.g., leaking tank/drum, high hazard or toxic material in small volumes) and potential for significant exposure (e.g., mercury vapors in one small house), not the square area of the site. In essence, it is the significance of the exposure or potential exposure that drives the urgency of the response.

    Libby Montana and BoRit are two completely different sites. Some of the significant differences are the amount of precipitation, the type of contaminant, the vegetation, and most important, the exposure. These are all important reasons that the BoRit experience may vary from the experience in Libby, MT.

    The average monthly precipitation in Libby, MT is 1.53 inches compared to 3.99 inches in Ambler, PA (weather.com). The most common way to reduce asbestos emissions during renovation, demolition, cutting or stripping of asbestos material is to use a wetting agent throughout to keep asbestos from becoming airborne. At BoRit, the moisture content in the soil may help minimize release of asbestos fibers into the air.

    The difference in the types of asbestos found at Libby versus Ambler is also important. The asbestos found in Libby, MT is naturally occurring vermiculite and zonolite. At BoRit we are talking about asbestos-containing material (ACM) waste, not pure asbestos. The Remedial Investigation/Feasibility Study data describe the ACM material at BoRit as being moist or wet.
    There are several reasons to suspect that unlike Libby, BoRit may not have served as a significant source of community exposures to asbestos fibers over the years. These include the soil cover placed on the Site in the 1960s, the subsequent growth of natural vegetation over much of the Site, and the closure of the majority of the Site to residents and potential ground disturbing activities since the mid 1980s.
    Being a worker or household contact (i.e., wife or child of worker coming home with fibers on clothing) at Libby was very important to your risk of developing disease. Also being male, a pile player (i.e., children playing on vermiculate piles), your age and smoking history were also correlated to disease. The point being that these were high exposure scenarios or in the case of smoking, compounding behavior.  Environmental exposures almost always required exposure through multiple pathways to be linked with disease and Libby had every pathway conceivable. Complicating all this was a high "background" of asbestos in the community’s air leading to additional exposure for all groups.

    It is important to remember that EPA is assessing the current risk to the community from airborne asbestos fibers from the Site. EPA understands that before the NPL Site was covered and while the plant was still in operation, the risk of exposure to the community might have been higher than what EPA found based on the October and November 2006 air sample results.

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