New York City and federal officials have chosen five public schools, one in each borough of the city, for a pilot study to assess the environmental risks posed by PCBs found in caulk used in older school buildings.
PCBs, or polychlorinated biphenyls, are highly toxic chemical compounds. PCBs were widely used in construction materials and electrical products in many buildings from the 1950s until their phase-out by the US EPA in 1978.
Long-term exposure when PCBs are released from the caulk into the air, or through direct contact, can result in cancer and affect immune and reproductive systems.
See NY Times story at: http://cityroom.blogs.nytimes.com/2010/03/25/schools-chosen-for-pcb-study/