Chromium-6: Health and Life-Cycle Hazards

Hexavalent chromium, or chromium-6 (CrVI), hit the news recently when a study found the chemical in the tap water of several major U.S. cities. A groundwater pollutant notorious from the 2000 hit movie “Erin Brockovich,” the chemical in vapor form is also a regulated occupational hazard. Should we be taking a more critical look at chrome plating and stainless steel?

Not all chromium is created equal. In its more stable trivalent form (CrIII), the metal does not normally endanger human health. And after unstable CrVI enters the body, it quickly reduces to CrIII. But cell damage occurs in the process, and CrVI is a known carcinogen when inhaled as well as a possible carcinogen when ingested. A variety of protective coatings, dyes, and pigments used for cars and boats as well as leather-tanning chemicals contain the metal. But aside from chrome-plated products, including solar collectors coated with high-efficiency “black chrome,” the manufacture of most building materials does not directly involve CrVI. The chromium that makes stainless steel “stainless” is the relatively benign non-valent chromium (Cr0), although welding stainless steel can generate CrVI fumes. Metal building products manufactured with CrVI do not generally present a health hazard once in use.