The environmental fate of diethylene glycol dinitrate (DEGDN) in surface waters is dominated by photolysis with surface half-lives ranging from 15 days in summer to 59 days in winter at 40.degree. N. The environmental quantum yield is 0.18. Photolysis of DEGDN initially forms nitrate ion and 2-hydroxyethyl nitratoacetate; the latter photolyzes further to 1- and 2-carbon acids and additional nitrate. DEGDN biotransforms with a second-order rate constant of 3.9 .times. 10-11 mL cell-1h-1, corresponding to a half-life of about 2 years in a typical surface water. Intermediate biotransformation products were observed but were further transformed and did not accumulate. DEGDN is expected to move readily through soils because it had low soil sorption coefficients Kp of 2 and 0.8 g mL-1 on EPA-5 and EPA-18 sediments, respectively. Abiotic reduction occurred rapidly in lake and river sediments but the importance of this process for overall fate is difficult to quantitate. Other fate parameters measured at 25.degree. C were a water solubility of 3900 mg L-1, octanol/water partition coefficient of 9.6 (dimensionless), Henry's constant of < 10-6 (dimensionless), base-catalyzed hydrolysis constant of 7 .times. 10-7 M-1s-1, neutral hydrolysis constant .ltoreq. 2 .times. 10-8s-1, and biouptake constants of <10 g dry cells/g water for Anabena flos-aquae and Selenastrum capricornutum.