The U.S. Environmental Protection Agency (EPA) describes polychlorinated biphenyls, more commonly known as PCBs, as belonging to a broad family of man-made organic chemicals known as chlorinated hydrocarbons. PCBs have been identified as probable human carcinogens and may also cause a variety of non-cancer health effects.
PCBs were domestically manufactured from 1929 until manufacturing was banned in 1979. They have a range of toxicity and vary in consistency from thin, light-colored liquids to yellow or black waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications.
The EPA goes on to state that although no longer commercially produced in the United States, PCBs may be present in products and materials produced before the 1979 ban. The agency is concerned that there was potential widespread use of PCB-containing building materials in schools and other buildings constructed or renovated between about 1950 and 1979.
To help protect people from indoor exposures, the EPA has provided important information about PCBs in building materials. Research results posted by the agency, about PCBs in school buildings, include the following:
• Caulk put in place between 1950 and 1979 may contain as much as 40 percent PCBs and can emit PCBs into the surrounding air. PCBs from caulk may also contaminate adjacent materials such as masonry or wood.
• Fluorescent lighting fixtures that still contain their original PCB-containing light ballasts have exceeded their designed lifespan, and the chance for rupture and emitting PCBs is significant.
• Some building materials (e.g., paint and masonry walls) and indoor dust can absorb PCB emissions and become potential secondary sources for PCBs. When the primary PCB-emitting sources are removed, the secondary sources often emit PCBs.
The agency recommends that building materials suspected of containing PCBs be tested directly for their presence and be properly removed if renovations are planned in a building.
These are just a few things to know about PCBs in building materials. To learn more about this or other building science, industrial hygiene, environmental, health or safety issues, please visit the websites shown below.
Clark Seif Clark [ Ссылка ]
EMSL Analytical, Inc. [ Ссылка ]
LA Testing [ Ссылка ]
Zimmetry Environmental [ Ссылка ]
Healthy Indoors Magazine [ Ссылка ]
