SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez nos Conditions d’utilisation et notre Politique de confidentialité.
SlideShare utilise les cookies pour améliorer les fonctionnalités et les performances, et également pour vous montrer des publicités pertinentes. Si vous continuez à naviguer sur ce site, vous acceptez l’utilisation de cookies. Consultez notre Politique de confidentialité et nos Conditions d’utilisation pour en savoir plus.
Assessment and Management of Polychlorinated Biphenyls in Caulking [Newsletter]
ASSESSMENT AND MANAGEMENT OF POLYCHLORINATED BIPHENYLS IN
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.
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
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
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
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
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
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