Where It Comes From
Production and use of azo/diarylide pigments; releases from manufacturing plants and hazardous waste sites; binds to soils/sediments and can persist; some pigments may break down to release small amounts [1][4].
How You Are Exposed
Breathing dusts or skin contact at work; contact with contaminated soil/sediment; drinking contaminated water near facilities or waste sites; exposure from finished pigmented products is generally low [1][4].
Why It Matters
Causes tumors in animals; NTP lists it as “reasonably anticipated to be a human carcinogen”; IARC classifies it as Group 2B (possibly carcinogenic). High exposures may affect the liver, bladder, and blood; can irritate skin and eyes [1][2][3].
Who Is at Risk
Workers making or using these pigments, maintenance/cleanup crews, and people living near current/former dye or pigment plants or contaminated sites [1].
How to Lower Your Exposure
Use closed systems, local exhaust, gloves/protective clothing, and appropriate respirators at work; wash up and change before going home; avoid disturbing contaminated soils; check local water/fish advisories; use wet/HEPA methods when cutting/sanding pigmented materials; dispose as directed [1][4].
References
- [1]ATSDR. ToxFAQs for 3,3'-Dichlorobenzidine. Agency for Toxic Substances and Disease Registry.
- [2]NTP. Report on Carcinogens: 3,3'-Dichlorobenzidine and 3,3'-Dichlorobenzidine Dihydrochloride. National Toxicology Program.
- [3]IARC. 3,3'-Dichlorobenzidine. IARC Monographs; Group 2B.
- [4]EPA IRIS. 3,3'-Dichlorobenzidine (CASRN 91-94-1). U.S. Environmental Protection Agency.