Toxicity Profiles

RAGs A Format for Chromium - CAS Number 7440473

Elemental chromium does not occur in nature, but it is present in ores, primarily chromite. Chromium can be found in rocks, animals, plants, soil, and in volcanic dust and gases. Chromium is present in the environment in several different forms (oxidation states). The most common forms are chromium(0), chromium(III), and chromium(VI). No taste or odor is associated with chromium compounds. Chromium(III) occurs naturally in the environment and is an essential nutrient that helps the body use sugar, protein, and fat.. Chromium(VI) and chromium(0) are generally produced by industrial processes. The metal chromium, chromium(0), is used for making steel. Chromium(VI) and chromium(III) are used for chrome plating, dyes and pigments, leather tanning, and wood preserving.

Chromium enters the body through the lungs, digestive tract and, to a lesser extent, the skin. Inhalation is the most important route for occupational exposure. Non-occupational exposure occurs via ingestion of chromium-containing food and water. Breathing high levels of chromium(VI) can cause irritation to the nose, such as runny nose, nosebleeds, and ulcers and holes in the nasal septum. Ingesting large amounts of chromium(VI) can cause stomach upsets and ulcers, convulsions, kidney and liver damage, and even death. Skin contact with certain chromium(VI) compounds can cause skin ulcers. Some people are extremely sensitive to chromium(VI) or chromium(III). Allergic reactions consisting of severe redness and swelling of the skin have been noted.

Several studies have shown that chromium(VI) compounds can increase the risk of lung cancer when inhaled. Animal studies have also shown an increased risk of cancer. There is also evidence for an increased risk of developing nasal, pharyngeal, and gastrointestinal carcinomas. Based on sufficient evidence for humans and animals, Chromium(VI) has been placed in the EPA weight-of-evidence classification A, human carcinogen. Chromium(III) is most appropriately designated a Group D -- Not classified as to its human carcinogenicity; however, the classification of chromium(VI) as a known human carcinogen raises a concern for the carcinogenic potential of trivalent chromium.

The following is a presentation of the toxicity information associated with Chromium

Chromium III (Insoluble Salts)

Noncarcinogenic Health Effects
  • The Oral Chronic Reference Dose is 1.50E+00 (mg/kg-day).
  • The Oral Chronic Reference Dose has a modifying factor of 10.
  • The Oral Chronic Reference Dose has an uncertainty factor of 100.
  • The Oral Chronic Reference Dose is based on the Ivankovic and Preussman study from 1975.
  • The overall confidence in the Oral Chronic Reference Dose is low.

  • The Dermal Chronic Reference Dose is 7.50E-03 (mg/kg-day).
  • The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.0050.

Chromium VI (Chromic Acid Mists)

Noncarcinogenic Health Effects

  • The Oral Chronic Reference Dose is 3.00E-03 (mg/kg-day).
  • The Oral Chronic Reference Dose has a modifying factor of 3.
  • The Oral Chronic Reference Dose has an uncertainty factor of 300.
  • The Oral Chronic Reference Dose is based on the MacKenzie et al. study from 1958.
  • The overall confidence in the Oral Chronic Reference Dose is low.

  • The Inhalation Chronic Reference Concentration is 8.00E-06 (mg/m3).
  • The Inhalation Chronic Reference Concentration has a modifying factor of 1.
  • The Inhalation Chronic Reference Concentration has an uncertainty factor of 90.
  • The Inhalation Chronic Reference Concentration is based on the Lindberg and Hedenstierna study from 1983.
  • The Inhalation Chronic Reference Concentration study target organ is nasal.
  • The Inhalation Chronic Reference Concentration study critical effect is septum atrophy.
  • The overall confidence in the Inhalation Chronic Reference Concentration is low.

  • The Dermal Chronic Reference Dose is 6.00E-05 (mg/kg-day).
  • The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.0200.

Carcinogenic Health Effects
  • The Inhalation Unit Risk is 1.2E+01 (mg/m3)-1.
  • The Inhalation Unit Risk study target organ is lung.
  • The Inhalation Unit Risk study cancer type is Tumors.
  • The Inhalation Unit Risk is based on the Mancuso study from 1975.

Chromium VI (Particulates)

Noncarcinogenic Health Effects
  • The Oral Chronic Reference Dose is 3.00E-03 (mg/kg-day).
  • The Oral Chronic Reference Dose has a modifying factor of 3.
  • The Oral Chronic Reference Dose has an uncertainty factor of 300.
  • The Oral Chronic Reference Dose is based on the MacKenzie et al. study from 1958.
  • The Oral Chronic Reference Dose study critical effect is none observed.
  • The overall confidence in the Oral Chronic Reference Dose is low.

  • The Inhalation Chronic Reference Concentration is 1.00E-04 (mg/m3).
  • The Inhalation Chronic Reference Concentration has a modifying factor of 1.
  • The Inhalation Chronic Reference Concentration has an uncertainty factor of 90.
  • The Inhalation Chronic Reference Concentration is based on the Malsch et al. study from 1994.
  • The Inhalation Chronic Reference Concentration study target organ is nasal.
  • The Inhalation Chronic Reference Concentration study critical effect is septum atrophy.
  • The overall confidence in the Inhalation Chronic Reference Concentration is low.

  • The Dermal Chronic Reference Dose is 6.00E-05 (mg/kg-day).
  • The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.0200.

Carcinogenic Health Effects
  • The Inhalation Unit Risk is 1.2E+01 (mg/m3)-1.
  • The Inhalation Unit Risk study target organ is lung.
  • The Inhalation Unit Risk study cancer type is Tumors.
  • The Inhalation Unit Risk is based on the Mancuso study from 1975.