Information on sources of PCBs and levels in school environments is needed to improve risk management decision-making. ORD's NERL planned research to better understand and characterize PCB sources, emissions, environmental concentrations, and exposures in school environments. Research was also planned by ORD's NRMRL to perform laboratory studies of PCB sources and transport and to evaluate selected mitigation approaches. In order to better understand the significance of PCB-containing caulk and other building materials and components as a source of PCB exposures to children, teachers, and staff in school buildings, the ORD's NERL planned research to utilize a limited set of real-world measurements to: (1) characterize PCB-contaminated caulk and other potential primary and secondary sources of PCBs in school buildings, (2) characterize levels of PCBs in school air, dust, soil, and on surfaces and to investigate relationships between potential PCB sources and environmental levels, (3) apply an exposure model for estimating children's exposure to PCBs in schools with PCB sources, (4) evaluate which routes of exposure (e.g., inhalation, contact with surfaces or dust) are likely to be most important, and (5) provide information to assist in developing risk management practices for reducing exposure to PCBs in schools.