Some forms of chromium in air or water can be harmful in unusually high concentrations.
What is chromium?
Chromium is a naturally-occurring element found in several forms in rocks, animals, plants, soil, and volcanic dust and gases. It has no odor. The chemical symbol for chromium is Cr. Chromium is a component of crude oil.
There are several forms of chromium, which are described by different numbers in parentheses. The most common forms are elemental chromium (0), chromium (III), and chromium (VI). Chromium (III) occurs naturally in the environment and is an essential nutrient for the human body. Chromium (0) and chromium (VI) are generally produced by industrial processes.
Naturally-occurring chromium (III) is used as brick lining for high-temperature industrial furnaces and for making metals, alloys, and chemical compounds.
Chromium (0) is a steel-gray solid metal that is used for making steel and other alloys. It is also used in nuclear and high-temperature research.
Compounds of chromium (III) and (VI) are used for chrome plating, manufacturing dyes and pigments, leather tanning, and wood preserving. Smaller amounts are used in drilling fluids, rust and corrosion inhibitors, textiles, and toner for copying machines. Chromium (VI) is also used in water treatment, fireworks, photography, process engraving, lithography, and chemical synthesis.
Tobacco leaves and tobacco products, including cigarettes, contain chromium.
You can be exposed to chromium by breathing air that contains it, though the levels in air are usually low. You may also eat food that naturally contains chromium (III), such as vegetables, fruits, meat, yeast, and grain; this kind of chromium is an essential nutrient. You can be exposed to harmful chromium by drinking well water contaminated with chromium (VI) or having skin contact with chromium if you work in a facility that uses it.
Acidic foods that come into contact with stainless steel cooking utensils might contain higher levels of chromium than other foods because of leaching from the stainless steel. You can also be exposed by using wood preservatives, cement, cleaning products, textiles, and tanned leather.
Exposure levels of chromium will be higher if you live near hazardous waste sites containing chromium or industrial facilities that use chromium, including cement-producing plants; or if you live near waterways that receive industrial discharges from electroplating, leather tanning, and textile production. You can also be exposed if you live near busy roads, because emissions from automobile brake lining and catalytic converters contain chromium.
At work, you can be exposed to chromium by breathing contaminated air or having skin contact with chromium. Industries that may use chromium include stainless steel production and welding, chromate production, chrome plating, ferrochrome production, chrome pigment production, and leather tanning. Occupations that may use chromium include painters, copy machine maintenance workers, battery makers, candle makers, dye makers, printers, rubber makers, and cement workers.
You can also be exposed to chromium at home or at work, indoors or outdoors, through smoking cigarettes, or breathing second-hand smoke.
The health effects of chromium and its forms are varied because each form has a different toxicity.
Chromium (VI) and its compounds are listed as human carcinogens in the Fourteenth Report on Carcinogens published by the National Toxicology Program because they have been known to increase rates of lung cancer.
Accidental or intentional swallowing of large amounts of chromium (VI) can cause death, kidney and liver damage, and ulcers. Swallowing small amounts of chromium (VI) can cause unconsciousness, convulsions, vomiting, diarrhea, dizziness, and abdominal pain. Breathing high levels of chromium (VI) can irritate the nose and cause nosebleeds, ulcers, holes in the nasal septum, and asthma attacks. Skin contact with chromium (VI) compounds can cause skin ulcers or skin allergies.
Prolonged industrial exposure to chromium compounds can cause chronic bronchitis and sinusitis. Industrial exposure to chromium fumes can cause "metal fume fever," which is a flu-like illness with metallic taste, fever, chills, aches, tightness of the chest, and cough.
Long-term exposure to chromium (0) can damage lung tissue.
If you think you have been exposed to chromium, contact your health care professional.
For poisoning emergencies or questions about possible poisons, please contact your local poison control center at 1-800-222-1222.
This description is based on the information found in the Web links listed with this topic.
Chromium and Compounds. Haz-Map (National Library of Medicine)
Chromium Compounds (Environmental Protection Agency) (PDF — 68.80 KB)
Chromium Compounds. Hazardous Substances Data Bank (National Library of Medicine)
Chromium. ToxFAQs (Agency for Toxic Substances and Disease Registry)
Hexavalent Chromium (National Institute of Environmental Health Sciences)
Hexavalent Chromium (National Institute for Occupational Safety and Health)
Hexavalent Chromium (Occupational Safety and Health Administration)
Hexavalent Chromium and Other Chromium Compounds. Enviro-Health Links. (National Library of Medicine)
Hexavalent Chromium Compounds (National Cancer Institute)
Map of Releases of Chromium in the United States. TOXMAP (National Library of Medicine)
Last Updated: February 22, 2017