Prolonged exposure of chemical vapor deposited, polycrystalline ZnSe to high ac voltages in the presence of a 1 molal NaCl solution induces severe mechanical damage. The damage takes the form of defects which originate at the surface and grow intergranularly into the bulk with a bush-like morphology. Neither exposure to the salt solution in the absence of the high voltage nor low voltage dc electrolytic exposure produces the defects. The damage may be associated with an intergranular hydride phase or grain boundary impurity segregations present or formed during the environmental exposure.