A study has been completed to learn more about the fate and effects of ethylene oxide (EO) in the environment and especially to fill gaps revealed in a recently published in-depth survey of available literature. Key findings on this large-volume product (3 x 10⁹ kg/year) includes (1) desorption coefficient oalt water at 25° C and a chlorohydrin/glycol product ration one-tenth of literature estimate, (4) biooxidation of EO and derivatives at a rate indicating nonpersistence, and (5àquatic toxicity at moderate levels (e.g., 96-h LC₅₀ with magna of 212 mg/L, and 48-h LC₅₀ with brine shrimp of 745 mg/L). Also, literature cited indicates that in air ethylene oxide is nonpersistent due to washout by rain and degradation by free-radical processes. -- CAL