AbstractThe Society of the Plastics Industry, Inc., ad hoc Bisphenol A Task Group determined that freshwater and saltwater environmental effects testing on bisphenol A should be conducted. This decision was based upon the nation's high production capacity for bisphenol A, which is manufactured at many sites, its potential for entering the environment in substantial quantities and the general lack of relevant ecological effects data. The freshwater test results were as follows: the 96‐h EC50 algal toxicity toSelenastrum capricornutumwas 2.7 mg/L based on cell count, and 3.1 mg/L based on cell volume; the 48‐h EC50 to the invertebrateDaphnia magnawas 10 (9.2–11) mg/L; and the 96‐h LC50s to the fathead minnow,Pimephales promelas, was 4.7 (4.0–5.5) mg/L in a static test and 4.6 (3.6 to 5.4) mg/L in a flow‐through test. The saltwater test results were as follows: the 96‐h EC50 algal toxicity to the diatomSkeletonema costatumwas 1.0 mg/L based on cell count and relative fluorescence, and 1.8 mg/L based on chlorophyllacontent; the 96‐h LC50 to the mysidMysidopsis bahiawas 1.1 (0.92 to 1.2) mg/L; and the 96‐h LC50 to the Atlantic silverside,Menidia menidia, was 9.4 (8.3 to 11) mg/L.According to current U.S. Environmental Protection Agency standard evaluation procedures, bisphenol A was moderately to slightly toxic to the fish and invertebrates tested, with LC50 or EC50 values of from 1.1 to 10 mg/L. These data did not trigger freshwater or saltwater chronic tests. The acute toxicity data together with the fact that bisphenol A rapidly biodegrades in surface waters indicate a low potential for chronic exp