Where It Comes From
Made as a dye/pigment intermediate; can be present in manufacturing waste or released when some dyes break down [2][3].
How You Are Exposed
Mostly at work—breathing dust or vapors and skin contact with powders, wet cakes, or contaminated equipment; less often via air, dust, or water near facilities [3][4].
Why It Matters
Listed as “reasonably anticipated to be a human carcinogen” (NTP) and “possibly carcinogenic to humans” (IARC); causes tumors in animals and can irritate skin and eyes [1][2][4].
Who Is at Risk
Workers in dye/pigment manufacturing, printing/ink, textiles and leather, labs and maintenance; waste handlers; people living near production sites [3][4].
How to Lower Your Exposure
At work, use closed systems, local exhaust, protective gloves/eye protection, avoid dry sweeping, wash up and change clothes, and follow the SDS; in communities, follow local advisories and avoid potentially impacted water [4][3].
References
- [1]NTP. Report on Carcinogens: o-Dianisidine and o-Dianisidine Dihydrochloride. https://ntp.niehs.nih.gov/whatwestudy/assessments/roc
- [2]IARC Monographs. o-Dianisidine and its salts (Group 2B). https://monographs.iarc.who.int/list-of-classifications
- [3]EPA IRIS. o-Dianisidine (CASRN 119-90-4) Summary. https://iris.epa.gov/static/pdfs/0373_summary.pdf
- [4]CDC/NIOSH Pocket Guide to Chemical Hazards: o-Dianisidine. https://www.cdc.gov/niosh/npg/npgd0458.html