Workers in industries producing and using chromium are at greatest risk of its adverse effects.
Workers in industries that use chromium, especially stainless steel welding, chromate production, chrome plating, and chrome pigment industries, where exposure via inhalation of aerosols is primarily to hexavalent chromium
(Cr [VI]), are at increased risk of chromium's effects. An estimated 175,000 workers might be exposed to Cr (VI) in the workplace on a regular basis; the number is much greater if exposure to other valence states of chromium is also considered. In many occupations, workers are exposed to both trivalent chromium (Cr [III]) and Cr (VI), as soluble and insoluble materials.
Risk assessment is underway for residents living on landfill derived from chromium-containing solid wastes.
Residents near chromate production facilities might be exposed to higher-than-background levels of Cr (VI). There is also concern that residents whose homes have been built on landfill using slag from smelters or chromate-producing facilities might be exposed to chromium through inhalation and dermal contact. Groundwater contamination might increase exposure in persons using well water as a source of drinking water.
Coal and oil combustion contribute an estimated 1,723 metric tons of chromium per year in atmospheric emissions; however, only 0.2% of this chromium is Cr (VI). In contrast, chrome-plating sources are estimated to contribute 700 metric tons of chromium per year to atmospheric pollution, 100% of which is believed to be Cr (VI).
