NIOSH Pocket Guide to Chemical Hazards

3,3'-Dichlorobenzidine (and its salts)

CAS 91-94-1


RTECS DD0525000
Synonyms & Trade Names
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
DOT ID & Guide


NIOSH REL: Ca See Appendix A
OSHA PEL: [1910.1007] See Appendix B
IDLH Ca [N.D.] See: IDLH INDEX Conversion
Physical Description
Gray to purple, crystalline solid.
MW: 253.1
BP: 788°F
MLT: 271°F
Sol(59°F): 0.07%
VP: ?
IP: ?

Sp.Gr: ?
Fl.P: ?
UEL: ?
LEL: ?

Incompatibilities & Reactivities
None reported
Measurement Methods
NIOSH 5509; OSHA 65
See: NMAM or OSHA Methods
Personal Protection & Sanitation (See protection)
Skin: Prevent skin contact
Eyes: Prevent eye contact
Wash skin: When contaminated/Daily
Remove: When wet or contaminated
Change: Daily
Provide: Eyewash, Quick drench
First Aid (See procedures)
Eye: Irrigate immediately
Skin: Soap wash immediately
Breathing: Respiratory support
Swallow: Medical attention immediately
Important additional information about respirator selection
Respirator Recommendations (See Appendix E) NIOSH
At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus
(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters./Any appropriate escape-type, self-contained breathing apparatus
Exposure Routes inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms Skin sensitization, dermatitis; headache, dizziness; caustic burns; frequent urination, dysuria; hematuria (blood in the urine); gastrointestinal upset; upper respiratory infection; [potential occupational carcinogen]
Target Organs Bladder, liver, lung, skin, gastrointestinal tract

Cancer Site [in animals: liver & bladder cancer]
See also: INTRODUCTION   See ICSC CARD: 0481   See MEDICAL TESTS: 0074