The main route of metabolism of vinyl chloride is in the liver by cytochrome P450 enzymes. It is first metabolized to chloroethylene oxide, a highly reactive, short-lived epoxide that rapidly rearranges to form chloroacetaldehyde. These reactive metabolites are detoxified via conjugation with glutathione . The rapid metabolism and excretion limits the accumulation of vinyl chloride in the body .
In humans, at low doses vinyl chloride is largely excreted in the urine as thiodiglycolic acid, its excretion increasing with exposure to the parent compound . At higher doses when metabolism is saturated, the major route of excretion is exhalation of unchanged vinyl chloride. Excretion via faeces is only a minor route .