The NWRC Chemical Effects Database is a searchable database that contains bioassay records and data for chemicals analyzed and evaluated for repellency, toxicity, reproductive inhibition, and immobilization. Studies were conducted from 1943 to 1987 by the U.S. Department of Agriculture's National Wildlife Research Center (NWRC), its predecessors, and by the U.S. Geological Survey's Patuxent Wildlife Research Center (PWRC) (formerly part of the U.S. Fish and Wildlife Service). The online database comprises published data only. The entire database, including unpublished data, is currently searchable by NWRC staff.