Ninety-six-hour static acute toxicity tests were conducted in the laboratory to determine the effects of a 47 ml/m2 (50 gal/acre) application of Arosurf MSF (2 mole ethoxylate of isostearyl alcohol) on Fundulus similus, Palaemonetes pugio, Palaemonetes paludosus, Uca spp., Procambarus spp., Gammarus spp., Asellus spp., Streptocephalus seali, Physa spp., Laeonereis culveri and an unidentified amphipod. Test temperatures of 20-27 degrees C were based on the ambient water temperature for the season of the year when the desired life stages were more abundant. No acute toxicity was observed with any of the organisms exposed to this concentration of Arosurf MSF.