Because it is a liquid that does not bind well to soil, methylchloroform that makes its way into the ground can move through the ground and enter groundwater. Plants and animals are not likely to store methylchloroform. Effects of methylchloroform on human health and the environment depend on how much methylchloroform is present and the length and frequency of exposure. Effects also depend on the health of a person or the condition of the environment when exposure occurs. Breathing large amounts of methylchloroform for short periods of time adversely affects the human nervous system and the cardiovascular system.
Effects range from headaches, unsteadiness, and fatique to unconsciousness and death.
Methylchloroform also can cause irregular heart beat. Direct contact with liquid methylchloroform irritates the skin. Its vapor irritates the eyes, the nose, and the throat. These effects are not likely to occur at levels of methylchloroform that are normally found in the environment. Human health effects associated with breathing or otherwise consuming smaller amounts of methylchloroform over long periods of time are not known.