News release: "The U.S. Environmental Protection Agency today announced a series of steps that building owners and school administrators should take to reduce exposure to PCBs that may be found in caulk in many buildings constructed or renovated between 1950 and 1978. The agency is also conducting new research to better understand the risks posed by caulk containing PCBs. This research will guide EPA in making further recommendations on long-term measures to minimize exposure as well as steps to prioritize and carry out actions to remove the caulk to better protect public health. Polychlorinated biphenyls, or PCBs, are man-made chemicals that persist in the environment and were widely used in construction materials and electrical products prior to 1978. PCBs can affect the immune system, reproductive system, nervous system and endocrine system and are potentially cancer-causing if they build up in the body over long periods of time.