On June 26, 1975, the U. S. Environmental Protection Agency awarded contract no. 68-01-3259 to Versar, Inc. Under this contract, it was anticipated that Versar would be assigned a number of tasks to assess the microeconomic impacts of regulatory alternatives which the EPA would consider for various toxic substances. The first task assigned under this contract required Versar to review and summarize the existing data on the use of polychlorinated biphenyls and to identify the industrial segments that might be impacted by regulations limiting the use of PCBs.