Trioxide and Other Chromium VI Salts

Occupational exposure to chromium(VI) compounds has been related to an increased risk of lung cancer. Several hexavalent compounds of chromium, including chromium trioxide, are hsted in lARC Group 1 ( carcinogenic to humans ) and are classified as select carcinogens under the criteria of the OSHA Laboratory Standard. Long-term exposure to chromium trioxide or chromium(VI) salts may cause ulceration of the respiratory system and skin. Exposure to chromium trioxide by inhalation or skin contact may lead to sensitization. Chromium trioxide has exhibited teratogenic activity in animal tests. 

Chromium trioxide and certain other chromium(VI) compounds are useful as strong oxidizing agents in the laboratory, but appropriate precautionary measures should be taken when conducting these reactions. Chromium trioxide has been reported to react violently with a variety of substances, including readily oxidized organic compounds such as acetone, acetaldehyde, methanol, ethanol, diethyl ether, ethyl acetate, acetic acid, and DMF, and violent reactions may also occur on reaction with alkali metals, gaseous ammonia, phosphorus, and selenium. 

Because of their carcinogenicity, chromium(VI) compounds should be handled using the basic prudent practices of Chapter 5.C, supplemented by the additional precautions for work with compounds of high toxicity (Chapter 5.D). In particular, chromium trioxide should be handled in a fume hood to avoid the inhalation of dust, and impermeable gloves should be worn at all times to prevent skin contact. The practice of using chromate solutions to clean glassware should be avoided. 

Chromium trioxide should be stored in areas separated from readily oxidized materials. 

In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If chromium trioxide or other chromium compounds are ingested, give the person large amounts of water or milk and obtain medical attention immediately. If dust or aerosols of these compounds are inhaled, move the person to fresh air and seek medical attention at once. 

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