Chromium

Chromium is a gray, solid material that is found naturally in rocks, animals, plants, soil, and volcanic dust and gas. It is an essential nutrient for humans that promotes the metabolism of sugar, protein, and fat, so small amounts of chromium in the diet are necessary for good health.

Where does chromium come from?

Chromium exists naturally on the earth's surface, but releases to the atmosphere are usually attributed to human activities. Airborne chromium usually settles back to earth within 10 days, so chromium levels in the atmosphere are very low.

Airborne chromium releases result from the following:

• metal fabrication;
• cement production;
• use of asbestos-lined brakes;
• waste incineration;
• automotive catalytic converters;
• cooling towers that use chromate chemicals as rust inhibitors (currently being phased out); and
• fossil fuel (natural gas, oil, and coal) combustion.

Do electric utilities release chromium into the environment?

Yes. U.S. electric utilities are responsible for about 2% of human-induced chromium releases into the atmosphere each year. Since electric utilities are responsible for a very small amount of annual chromium releases in the U.S., it is unlikely that chromium from power plants poses a significant health risk.

How could I be exposed to chromium?

Exposure to chromium can occur in the following ways: food consumption (accounts for more than 96% of daily chromium exposure for most people); inhalation; drinking water; skin contact (occurs during the use of consumer products like wood preservatives, cement, cleaning products, textiles, and tanned leather).

People who work in industries that use chromium can be exposed to higher levels of the metals. The greatest exposure occurs in the following occupations: chromate production; stainless steel production; welding; chrome plating; chrome pigment production; leather tanning; painting; copy machine service and toner cartridge disposal; and production of batteries, dyes, and cement.

What does EPA say?

EPA has concluded that chromium from power plants readily converts to a form that does not pose a risk to human health.

The Agency does not consider the cancer risk from ingestion of chromium to be a serious health threat. Nonetheless, to protect safe drinking water, EPA has set a maximum level of 100 parts of chromium per billion parts of water (ppb). EPA has said that long-term exposure below this level is not expected to cause health effects. Standards from the Occupational Health and Safety Administration (OSHA) regulate the amount of chromium present in workplace air.

Where can I get more information?

• Electric Power Research Institute
  3412 Hillview Ave.
  P.O. Box 10412
  Palo Alto, California 94303
  phone (650)855-2000
  
  
• Integrated Risk Information System, U.S. Environmental Protection Agency.
  
  
• Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units - Final Report to Congress, Volume 1 and 2, U.S. Environmental Protection Agency, 1998.
  
  
• Statistical Abstract of the United States 1997, The National Data Book, U.S. Department of Commerce, Economics and Statistics Administration, Bureau of the Census, 1997.
  
  
• Toxicological Profile for Chromium, U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substance and Disease Registry, 1993.