Ethylene dichloride, a chlorinated hydrocarbon, is primarily used as an intermediate during the production of vinyl chloride and other commercially valuable compounds. The characteristic water solubility and vapor pressure of ethylene dichloride indicate that this compound will tend to presist in the hydrosphere and lithosphere; while its slow activity with peroxide radicals and ozone indicates atmospheric persistence as well. Industrial exposure is limited by Occupational Safety and Health regulations to 200 mg/cum (50 ppm). Ambient atmospheric measurements are not readily available. Inhalation of ethylene dichloride during acute exposure has been shown to produce central nervous system disorders as well as pathological effects in the liver, kidneys, and adrenals of humans, while chronic human exposure produces similar results. The no-lasting-effect level is quite high (1000 ppm for 1 hour and 3000 ppm for 6 minutes) indicating that detrimental exposure levels would have to be much greater. Although the compound does not appear to pose a significant environmental hazard, little information is available for assessment of potential long-term low level effects. As a result ethylene dichloride cannot be considered innocuous until additional health data is accumulated.