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Model of the benzidine molecule

What is benzidine?

Benzidine is a manufactured chemical that does not occur in nature. In the past, large amounts of benzidine were used to produce dyes for cloth, paper, and leather. It was also used in clinical laboratories for detecting blood, as a rubber-compounding agent, and in the manufacture of plastic films. However, benzidine has not been sold in the United States since the mid-1970s, and it is no longer used in medical laboratories or in the rubber and plastics industries.

How are people exposed to benzidine?

Inhalation and accidental ingestion are the main ways people can be exposed to benzidine-based dyes in the United States. As benzidine-based dyes were removed from both industrial and consumer markets and replaced with other types of dyes, the potential for exposure has declined.

Which cancers are associated with exposure to benzidine?

Occupational exposure to benzidine results in an increased risk of bladder cancer, according to studies of workers in different geographic locations.

Selected References:

  • Agency for Toxic Substances and Disease Registry. Toxic Substances Portal - Benzidine. Atlanta, GA: Centers for Disease Control and Prevention, 2014. Available online. Last accessed January 31, 2019.
  • Health Effects Notebook for Hazardous Air Pollutants. Benzidine Fact Sheet. Washington, DC: U.S. Environmental Protection Agency, 2000. Available online. Last accessed January 31, 2019.
  • National Institute of Occupational Safety and Health. Benzidine, NIOSH Pocket Guide to Chemical Hazards. Atlanta, GA: Centers for Disease Control and Prevention, 2010. Available online. Last accessed January 31, 2019.
  • National Toxicology Program. Benzidine and Dyes Metabolized to Benzidine, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Available online. Last accessed December 5, 2022.
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