The degradation of selected halogenated ethanes was studied in anoxic sediment-water suspensions at 1 to 20% sediment concentrations. Batch kinetic experiments were used to quantify decay. Eh measurements of all suspensions were below -100mV (vs SHE), indicating reduced environmental conditions. Hexachloroethane (HCA), 1,1,2,2-tetrachloroethane (TTCA), 1,2-diiodoethane (DIA) and 1,2-dibromoethane (DBA) were degraded within minutes to days, but 1,2-dichloroethane (DCA) remained in the system through 35 d, at which point the study was ended. The major route of transformation of these compounds in the system was vicinal dehalogenation. Rates of disappearance followed pseudo-first-order kinetics at low reactant concentrations and high sediment concentration.