The effects-based criteria identified in the 1977 ocean dumping regulations and associated guidelines for evaluating potential hazard of ocean-disposed wastes to aquatic organisms are reviewed. The use of these criteria, which provide for bioassay-based limiting permissible concentrations for physical phases of wastes to be compared with estimated environmental concentrations of the phases, is demonstrated in case studies of two wastes (acid-iron wastewater and dredged material) that are dumped in the ocean and one waste (formation water) that is discharged from an ocean outfall. The case studies present Lagrangian (exposure-time-dependent) assessments of the potential hazard of ocean-disposed wastes to plankton, as well as Eulerian (exposure-time-independent) evaluations of the potential hazard to nonplanktonic organisms. A plume study and models of different levels of sophistication are employed to estimate environmental concentrations of ocean-disposed materials.