281 TOXICOLOGY Risk assessment for chromium is affected by its oxida tion state. Trivalent chromium, which is the predominant form in the food supply, has low oral toxicity, at least par- tially because it is very poorly absorbed (8) A recent report has generated some controversy about the safety of chromium (III) supplements (47). Relatively high concentrations of chromium picolinate, chromium chloride, or chromium nicotinate were added to Chinese hamster ovary cells in culture. Chromium picolinate and picolinic acid tested positive in an assay used to predict mutagenicity, while chromium nicotinate and chromium chloride did not (47). There have been many supplemen- tation trials in humans with chromium chloride and with chelated chromium compounds without reports of toxic ity. However, because of the current widespread use of chromium supplements, more research would be appro- priate to evaluate the risk and cost/benefit ratios of triva lent chromium supplements (VI), a product of man On the other hand, chromium ufacturing, is included in health risk assessments at Environmental Protection Agency superfund sites (9) certain foods and substances in our gastroin testinal tract have substantial capacity for reduction of chromium (VI) to chromium (III). For example, Kuykendall et al. (48) gave volunteers 5 mg (96 pumol) of reduced to chromium with orange juice (prior to ingestion). They demonstrated no DNA-protein cross-links in leukocytes due to acute (ITI) or (VI) and suggested