Chromium is a naturally-occurring element found in rocks, animals, plants, and soil.

The three main forms of chromium are chromium(0), chromium(III), and chromium(VI). Small amounts of chromium(III) are considered to be a necessity for human health.

• manufacturing

Chromium is widely used in manufacturing processes.

• consumer products

Chromium can be found in many consumer products such as:

• wood treated with copper dichromate.
• leather tanned with chromic sulfate.
• stainless steel cookware.

Chromium can be found in air, soil, and water after release from the manufacture, use, and disposal of chromium-based products, and during the manufacturing process.

• air

Chromium does not usually remain in the atmosphere, but is deposited into the soil and water.

• water and soil

Chromium can change from one form to another in water and soil, depending on the conditions present.

You can be exposed to chromium by breathing air containing it or drinking water containing chromium. Releases of chromium into the air can occur from:

• industries using or manufacturing chromium
• living near a hazardous waste facility that contains chromium
• cigarette smoke

•  <10 ng/m³ in rural areas
• 0–30 ng/m³ in urban areas
• as a result of smoking, indoor air contaminated with chromium can be 10–400 times greater than outdoor air concentrations.

Chromium is occasionally detected in groundwater, drinking water, or soil samples. Some ways to be exposed to chromium include:

• drinking water containing chromium
• bathing in water containing chromium

A large number of workers are potentially exposed to chromium. The highest potential exposure occurs in the metallurgy and tanning industries, where workers may be exposed to high air concentrations.

The general population is most likely to be exposed to trace levels chromium in the food that is eaten. Low levels of chromium(III) occur naturally in a variety of foods, such as fruits, vegetables, nuts, beverages, and meats.

• inhalation

When you breathe air containing chromium, some of the chromium will enter your body through your lungs. Some forms of chromium can remain in the lungs for several years or longer.

• ingestion

A small percentage of ingested chromium will enter the body through the digestive tract.

• dermal contact

When your skin comes in contact with chromium, small amounts of chromium will enter your body.

Chromium(VI) is changed to chromium(III) in the body. Most of the chromium leaves the body in the urine within a week, although some may remain in cells for several years or longer.

Chromium(VI) compounds are more toxic than chromium(III) compounds. The most common health problem in workers exposed to chromium involves the respiratory tract. These health effects include irritation of the lining of the nose, runny nose, and breathing problems (asthma, cough, shortness of breath, wheezing). Workers have also developed allergies to chromium compounds, which can cause breathing difficulties and skin rashes.

The concentrations of chromium in air that can cause these effects may be different for different types of chromium compounds, with effects occurring at much lower concentrations for chromium(VI) compared to chromium(III) . However, the concentrations causing respiratory problems in workers are at least 60 times higher than levels normally found in the environment.

Respiratory tract problems similar to those observed in workers have been seen in animals exposed to chromium in air.

The main health problems seen in animals following ingestion of chromium(VI) compounds are to the stomach and small intestine (irritation and ulcer) and the blood (anemia). Chromium(III) compounds are much less toxic and do not appear to cause these problems.

Sperm damage and damage to the male reproductive system have also been seen in laboratory animals exposed to chromium(VI).

The International Agency for Research on Cancer (IARC) has determined that chromium(VI) compounds are carcinogenic to humans. The National Toxicology Program 11th Report on Carcinogens classifies chromium(VI) compounds as known to be human carcinogens.

In workers, inhalation of chromium(VI) has been shown to cause lung cancer. An increased in stomach tumors was observed in humans exposed to chromium(VI) in drinking water.

In laboratory animals, chromium(VI) compounds have been shown to cause tumors to the stomach,intestinal tract and lung.

There are no studies that have looked at the effects of chromium exposure on children. It is likely that children would have the same health effects as adults. We do not know whether children would be more sensitive than adults to the effects of chromium.

There are no studies showing that chromium causes birth defects in humans. In animals, some studies show that exposure to high doses during pregnancy may cause miscarriage, low birth weight, and some changes in development of the skeleton and reproductive system. Birth defects in animals may be related, in part, to chromium toxicity in the mothers.

Chromium is a component of tobacco smoke. Avoid smoking in enclosed spaces like inside the home or car in order to limit exposure to children and other family members.

In the past, pressure treated wood used chromated copper arsenate; however, the use of this product in residential settings was discontinued effective December 31, 2003. Avoiding older pressure treated lumber can reduce your risk of exposure to chromium. You may also have your water tested to ensure that you are not exposed to high levels of chromium.

Clothing or items removed from the workplace may contain chromium if you are employed in a setting where occupational exposure is significant. Therefore, common sense hygiene and laundry practices may help avoid unnecessary exposures.

Since chromium is a required nutrient in the body and is normally present in food, chromium is normally present in blood, urine, and body tissues.

Higher than normal levels of chromium in blood or urine may indicate that a person has been exposed to chromium. However, increases in blood and urine chromium levels cannot be used to predict the kind of health effects that might develop from that exposure.

The EPA has determined that exposure to chromium in drinking water at concentrations of 1 mg/L for 1 day or 10 days is not expected to cause any adverse effects in a child.

The FDA has determined that the chromium concentration in bottled drinking water should not exceed 0.1 mg/L.

OSHA set a legal limit for chromium(VI) of 0.0005 mg/m³ chromium in air averaged over an 8-hour work day, for chromium(III) of 0.5 mg/m³ chromium in air averaged over an 8-hour work day, and for chromium(0) of 1.0 mg/m³ chromium in air averaged over an 8-hour work day.