Data on acute and chronic toxicity of permethrin, fenvalerate, cypermethrin, and flucythinate to marine invertebrates and fishes are reviewed. Laboratory toxicity tests were conducted with sediment-source fenvalerate and cypermethrin under static and flow-through conditions to determine the degree of contamination necessary to achieve acute, lethal effects on mysids (Mysidopsi bahia), grass shrimp (Palaemonetes pugio), and pink shrimp (Penaeus duorarum). Mortality was observed among test animals only in systems where concentrations of sediment-source pyrethroids were sufficient to establish lethal concentrations in overlying water through sediment-water partitioning. For fenvalerate, lethal effects occurred at sediment concentrations of 0.1 mg/kg (static and flow-through) for mysids and grass shrimp and 10 mg/kg for pink shrimp. Sediment concentrations of cypermethrin (0.1 mg/kg (static) or 1.0 mg/kg (flowthrough)) resulted in mortality among mysids and grass shrimp, whereas 1.0 mg/kg was the only test concentration that caused mortality among pink shrimp in static or flow-through tests systems.