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Chemical Sampling Information (CSI)
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General Description

Synonyms: 4,4'-Diamino-3,3'-dichlorobiphenyl; Dichlorobenzidine base; o,o'-Dichlorobenzidine; 3,3'-Dichlorobiphenyl-4,4'-diamine; 3,3'-Dichloro-4,4'-biphenyldiamine; 3,3'-Dichloro-4,4'-diaminobiphenyl

OSHA IMIS Code Number: 0869

Chemical Abstracts Service (CAS) Registry Number: 91-94-1

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: DD0525000

NIOSH Pocket Guide to Chemical Hazards, 3,3'-Dichlorobenzidine (and its Salts): chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

OSHA Permissible Exposure Limit (PEL):
General Industry: 29 CFR 1910.1007 requirements identical to 29 CFR 1910.1003 -- 13 Carcinogens (4-Nitrobiphenyl, etc.)-- Cancer-Suspect Agent

Construction Industry: 29 CFR 1926.1107 requirements identical to 29 CFR 1910.1003 -- 13 Carcinogens (4-Nitrobiphenyl, etc.) -- Cancer-Suspect Agent

Maritime: 29 CFR 1915.1007 requirements identical to 29 CFR 1910.1003 -- 13 Carcinogens (4-Nitrobiphenyl, etc.) -- Cancer-Suspect Agent
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): Exposure by all routes should be carefully controlled to levels as low as possible; Skin; Appendix A3 - Confirmed Animal Carcinogen with Unknown Relevance to Humans

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): Appendix A - NIOSH Potential Occupational Carcinogens

Health Factors

Carcinogenic Classification:
Environmental Protection Agency (EPA): Group B2, probable human carcinogen

International Agency for Research on Cancer (IARC): Group 2B, possibly carcinogenic to humans [1 MB PDF, 454 pages]

National Toxicology Program (NTP): Reasonably anticipated to be a human carcinogen [122 KB PDF, 3 pages]
Potential Symptoms: Skin sensitization; dermatitis; headache; cough, sore throat; dizziness; caustic burns; frequent urination, dysuria, hematuria (blood in the urine); GI upset; upper respiratory infection; [potential occupational carcinogen]

Health Effects: Bladder cancer (HE1)

Affected Organs: Bladder, liver, lungs, skin, GI tract

  1. 3,3'-Dichlorobenzidine (and its salts) is an OSHA Regulated Carcinogen (29 CFR 1910.1007)
  2. Mono- and di-N-acetylated metabolites of 3,3'-dichlorobenzidine have been identified in urine.
  3. Adducts of 3,3'-dichlorobenzidine and N-acetyl-3,3'-dichlorobenzidine to hemoglobin in rats treated with 3,3'-dichlorobenzidine have been quantified as a possible method for biological monitoring of occupational exposure.
  4. Similar adducts with hepatic lipids were found in rats given a single oral dose of radiolabeled 3,3'-dichlorobenzidine.
  5. Such adducts are thought to occur with reactive metabolites, possibly nitroso derivatives, formed by the action of cytochrome P450 4B1 or other P450s.
  6. Absorption of 3,3'-dichlorobenzidine applied in acetone to the skin of rats was reported to be about 50% in 24 hours.
Date Last Revised: 11/02/2005

Literature Basis:
  • NIOSH Pocket Guide to Chemical Hazards: 3,3'-Dichlorobenzidine (and its Salts).
  • International Chemical Safety Cards (WHO/IPCS/ILO): 3,3'-Dichlorobenzidine.
  • EPA Air Toxics Website: 3,3'-Dichlorobenzidine. U.S. Environmental Protection Agency Technology Transfer Network.
  • No Author: 3,3'-Dichlorobenzidine and Its Dihydrochloride CAS Nos. 91-94-1 and 612-83-9 [122 KB PDF, 3 pages]. Report on Carcinogens (latest edition); U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program.
  • Iba, M.M., Lang, B., Thomas, P.E. and Ghosal, A.: Covalent interaction of 3,3'-dichlorobenzidine with hepatic lipids. Enzymatic basis and stability of the adducts. Biochem. Pharmacol. 40(3): 581-587, 1990.
  • Imaoka, S., Yoneda, Y., Matsuda, T., Degawa, M., Fukushima, S. and Funae, Y.: Mutagenic activation of urinary bladder carcinogens by CYP4B1 and the presence of CYP4B1 in bladder mucosa. Biochem. Pharmacol. 54(6): 677-683, 1997.
  • Joppich-Kuhn, R., Hänggi, R., Sagelsdorff, P., Smith, A.E., Weideli, H.J. and Joppich, M.: Determination of dichlorobendidine-hemoglobin adducts by GC/MS-NCI. Int. Arch. Occup. Environ. Health 69(4): 240-246, 1997.
  • Pohanish, R.P. (editor): 3,3'-Dichlorobenzidine (and its Salts). In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 804-806.
  • Shaw, P.V. and Guthrie, F.E.: Dermal absorption of benzidine derivatives in rats. Bull. Environ. Contam. Toxicol. 31(1): 73-78, 1983.

Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • sampling media: Coated Glass Fiber Filters (37 mm) in 3 piece cassette. Coating is Sulfuric Acid.
    maximum volume: 100 Liters   maximum flow rate: 1.0 L/min
    current analytical method: Gas Chromatography; GC/ECD
    method reference: OSHA Analytical Method (OSHA 65)
    method classification: Fully Validated
    note: Within ten hours after sampling, transfer filter to glass vial containing 2 mL deionized water. Sample must be shipped and stored at 0 deg C or colder. Analyze as soon as possible. Filters may be obtained by OSHA personnel from SLTC.
Wipe Sampling Method:
  • sampling media: Glass Fiber Filter.
Bulk Method: Limit the amount of bulk submitted to one gram or one mL.

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Page last updated: 09/05/0006

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