Halogenated alkenes are a group of commercially important chemicals. For example tetrafluoroethylene is the monomer used for the production of poly- tetrafluoroethylene, hexachloro-1:3-butadiene is a by-product from the manufacture of chlorinated solvents and perchloroethylene is widely used as a dry cleaning agent. Due to possible exposure to haloalkenes and the nephrotoxicity observed in animal studies, concern has been expressed for the potential of these compounds to cause toxicity to man. Animal studies have shown that these compounds undergo inter-organ metabolism and are bioactivated by enzymes of glutathione processing. The metabolites are delivered to the kidney where they cause proximal tubular cell necrosis. This site-specific toxicity is due to accumulation of the metabolites via specific transport mechanisms and bioactivation via the enzyme C-S lyase present in high amounts in the proximal tubules. The aim of this research was to investigate the mechanisms of toxicity of haloalkene S'-conjugates in vitro using cultures of rat and human proximal tubular cells. This study demonstrates that human proximal tubular cells are sensitive to haloalkene. -conjugate toxicity, particularly DC VC. Human exposuredata has shown that workers exposed to trichloroethylene (Bimer et al, 1993) and perchloroethylene (Mutti et al, 1992) excrete nephrotoxic metabolites and markers of renal damage respectively. In the light of these findings and the toxicity of DCVC in HPT cells, exposure to halogenated alkenes should be controlled and those exposed monitored.