PCBs are man-made compounds that comprise a class of 209 structurally-related chemicals (or congeners) which were sometimes used in the manufacture of certain building materials, such as caulking or sealants, from the 1950s through the 1970s. PCBs were added to building sealants for added strength, durability, flexibility, and resistance to degradation. Over 75 million kilograms of PCBs were reported to have been sold in the U.S. from 1958 through 1971 for use as plasticizers or as a component of numerous industrial products (NIOSH, 1975). PCBs have been reported to be a hazard to human and ecological receptors (ATSDR, 2000).

A large number of buildings may be constructed with PCB-containing materials based on current information about PCB uses in building products. Over 800,000 government and non-government buildings that comprise 12 billion square feet of interior space are estimated to have been constructed between 1958 and 1971. In addition, forty-six percent of elementary schools in the U.S. (approximately 55,000 schools) are estimated to have been built during that time period according to results from a survey of indoor air quality programs in schools (EPA, 2012).

In 1979, the U.S. Environmental Protection Agency (EPA) banned the manufacture of new products containing PCBs and developed regulatory requirements for the storage, labeling, use, and disposal of materials containing PCBs at levels above certain regulatory thresholds.

Typical caulked / sealed joints on buildings most often include

• Perimeter caulking around the frames of interior and exterior window and doors
• Glazing sealants between glass panes and frames or between metal frames
• Building expansion and control joints
• Miscellaneous - roof sealants, pipe penetration or ventilation duct seam sealants, or any number of building repair sealants

If a building has been constructed or renovated using PCB-containing caulking or sealants, PCB impacts may not be limited to the caulking itself. Through mechanisms such as weathering, leaching, or deterioration, PCBs may also be found in the materials adjacent to the caulking, including concrete, brick, or metal surfaces. PCBs have also been known to impact ground surfaces surrounding a building, including soils or paved areas.