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Assessment and Management of Polychlorinated Biphenyls in Caulking [Newsletter]


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Assessment and Management of Polychlorinated Biphenyls in Caulking [Newsletter]

  1. 1. ® SUMMER 2010 ASSESSMENT AND MANAGEMENT OF POLYCHLORINATED BIPHENYLS IN CAULKING Increased attention has been given to the occurrence of polychlorinated biphenyls (PCBs) in building materials, notably in caulking products, due to the potential for health hazards to humans via exposure. This attention and building-owner concerns over liability have given rise to many questions regarding regulatory requirements and, unfortunately in some cases, too expensive and potentially unnecessary responses. PCBs are man-made organic compounds comprised of two benzene-ring molecules with one to ten bonded chlorine atoms, and were manufactured in the United States from the late 1920s to 1977. Prior to 1977, PCBs were widely used as stabilizers, plasticizers, flame retardants, insulators, and coolants in products including oils, paints, roofing material, insulation, adhesive, and caulking. Congress prohibited the manufacture of PCBs and PCB-containing products with the passage of the Toxic Substance Control Act (TSCA, Chapter 30 Code of Federal Regulations Part 761) in 1977 in response to studies suggesting strong links between exposure to some types of PCBs and the occurrence of cancer and serious non-cancerous health effects in animals. The United States Environmental Protection Agency (USEPA) has classified PCBs as probable human carcinogens. From approximately 1950 to 1977, PCBs were sometimes added to caulking during its manufacture to improve the caulking's plasticity, and analyses have detected up to 300,000 parts per million (ppm) PCBs in some caulking products. Not all caulking products manufactured from 1950 to 1977 contain PCBs, but caulking containing greater than 50 ppm of PCBs were widely applied to seal gaps around windows and door frames, masonry joints, and to create airtight and watertight seals. Although the TSCA contained provisions for the authorized use of some specific PCB-containing equipment and materials, it prohibited the continued use of all other types of equipment and materials containing PCBs at concentrations greater than 50 ppm.
  2. 2. ® The USEPA and the National Institute of Occupational Safety and Health (NIOSH) recommend PCB concentrations in indoor-air not to exceed 1 microgram per cubic meter (ug/M3 ). The USEPA has also identified a low level of 20 nanograms per kilogram body weight per day (ng/Kg per day) as the reference dose above which adverse health effect may occur. Unfortunately, although PCBs generally have relatively low volatilities, evaporation of PCBs into indoor air and particulates from deteriorating building materials containing PCBs can result in that USEPA reference dose being exceeded in some buildings. Under TSCA, the USEPA also regulates media, such as soil and masonry that contain PCBs if the PCBs originated from a material that contained PCBs at a concentration greater than 50 ppm. Although TSCA regulations do not require building owners to test the PCB content of caulk still serving its original purpose, if testing is conducted and PCB concentrations above the 50 ppm regulatory limit are detected, TSCA regulations require its removal and decontamination or removal of other impacted media. Caulk containing PCBs at levels less than 50 ppm may remain in place. A TSCA provision allows greater than 50 ppm PCB-containing materials to remain in place if the USEPA approves a site-specific risk -based approach in accordance with 40 CPR § 761.62(c) if it will not present an unreasonable risk of injury to health or the environment; however, such approvals are rare and the future use restrictions applied to such approvals are often seen as largely negating any benefit. PCB caulk and materials coated with the PCB caulk that are removed during demolition or renovation are considered PCB bulk-product wastes, defined at 40 CFR § 761.3, and are required to be handled, transported, and disposed of in accordance with applicable State and federal waste disposal regulations, including TSCA 40 CFR § 761.62. Waste materials containing greater than 50 ppm of PCBs may only be disposed of at licensed hazardous waste or TSCA waste disposal facilities, and the cost for its transportation and disposal is significantly higher than for other typical demolition debris. Successful PCB bulk-product abatement projects must minimize the spread of PCBs and prevent the recontamination of cleaned areas. Media, including soil and masonry impacted by a source containing greater than 50 ppm of PCBs are considered remediation wastes, and TSCA 40 CFR § 761.61 applies to its remediation and disposal, rather than 40 CFR § 761.62. The USEPA specifies
  3. 3. ® that PCB concentrations in impacted media be reduced to less than 1 ppm to allow for unrestricted use in "high occupancy areas" (e.g., areas where individuals may be present for 335 hours or more per year). Considering that PCB concentrations in caulk can approach 300,000 ppm, proper maintenance and removal of caulk can reduce the potential that a costly soil remediation will also be needed. In 2004, samples of suspected PCB-containing caulk from 24 buildings in the Boston area were analyzed, and 8 buildings were found to contain caulk with greater than 50 ppm of PCBs (Herrick, R., 2004). PCB-caulk abatement can be very time consuming and disruptive, and the costs are often high. From 2001 to 2002, the University of Rhode Island spent an estimated $3,800,000 to remediate PCB-containing caulk, including the replacement of 220 windows from an 8-story building (URI, 2001). The University of Massachusetts spent an estimated $2,000,000 to abate PCB-containing caulk and impacted soil, asphalt, and carpets from a research center (Daily Hampshire Gazette, July 06, 2007). Abatement costs can also escalate because PCBs can impact indoor air and affect air-handling systems, sometimes necessitating comprehensive testing and decontamination, or replacement, of the air-handling systems. Encapsulating or sealing PCBs in place is not currently allowed by the USEPA. However, on January 2010, USEPA Region 2 entered into an agreement with New York City (the City) outlining how the City should proceed to assess schools for the presence of PCB caulk prior to the preparation of abatement plans. The USEPA Region 2 agreement acknowledged that an acceptable remedial approach may be cleaning, improving ventilation, and replacement of deteriorating caulk, suggesting that intact PCB caulk may be allowed to remain if exposure levels can be shown to be acceptable. The USEPA has acknowledged that the link between the concentrations of PCBs in caulk and PCBs in the air or dust, and actual human exposure levels, is not well understood. The USEPA is doing research to better determine the sources and levels of PCBs in building materials and to evaluate different strategies to reduce exposures. On April 7, 2010, the USEPA published an Advanced Notice of Proposed Rulemaking (ANPRM) indicting that they were undertaking a reassessment of certain TSCA requirements including rules regarding the use of the 50 ppm threshold for those PCB products excluded from use-authorization. Those excluded products include, but are not limited to, caulk, adhesives, paint, coatings, and grease. The 50 ppm level was based "almost entirely on
  4. 4. ® economic considerations" and not on risk assessment calculations. The USEPA is seeking comments on whether the 50 ppm level "should be changed given the recent realization that the use of PCBs in caulk may be widespread and may be an undue burden for schools" if the use-authorization exclusion continues at 50 ppm. Building owners concerned about liability from PCB-containing building materials should retain a professional environmental consultant with experience in environmental investigation and testing to prepare a detailed plan to guide testing and abatement. Alternatively, if PCB exposure risk and liability is currently acceptable, building owners may wish to consider retaining an experienced environmental consultant to prepare a PCB Operations and Maintenance (O&M) Plan to guide testing and disposal of wastes generated during future renovations and demolitions. Abatement plans and PCB O&M Plans should consider the potential presence of asbestos and lead paint-containing building materials and the benefits potentially available by concurrently addressing the testing, abatement, and disposal requirements for those materials. Well prepared abatement and O&M Plans should also address not only federal requirements but also state-specific requirements, transportation and manifesting requirements, documentation, and verification. The consultant's understanding of PCB fate and transport characteristics is critical, especially if indoor air testing is to be conducted since concentrations of PCBs in indoor air can vary seasonally, daily, and hourly and an improper testing protocol can result in high biased results. Likewise, a correct understanding of how to apply appropriate sample compositing schemes and analytical methods can greatly lower assessment costs. William J. Gibbons - Associate and Senior Scientist