3.3- dichlorobenzidine

Used in the production of yellow and red pigments for the printing ink, textile, paper, paint, rubber, plastic, and related industries 

Toxicology. 3,3 -Dichlorobenzidine (DCB) is carcinogenic in several animal species. 

The acute LD50 of DCB in rats has been estimated to be 7100mg/kg for the free base and 3800mg/kg for the dihydrochloride salt. Considering these high LD50 values, acute lethality in man after oral exposure is not expected to be very likely.  

Dermatitis was cited as the only verified health problem encountered by workers in contact with DCB at a DCB manufacturing plant. Applied to the skin of rabbits DCB dihydrochloride caused no discernable reaction instilled in the rabbit eye 20 mg (as 0.1 ml of 20% corn oil suspension) produced erythema, pus, and corneal opacity. No effects were reported when 100 mg of the free base was placed in rabbit eyes. 

Existing animal data shows that DCB induces tumors at a variety of sites in several animal species.  

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One area which requires special comment is a study (13) which showed that certain diaryUde pigments processed ia polymers above 200°C and particularly above 240°C decompose to give off 3,3 -dichlorobenzidine, an animal carciaogen. As a consequence diaryUde pigments (not, however, condensation disazo pigments) are not recommended for use ia any appHcations where they might be exposed to temperatures exceeding 200°C. 

Orthotolidine and its salts Dianisidine and its salts Dichlorobenzidine and its salts In manufacture, formation or use of these substances... 

Dichloro-1 -nitroethane o-Dichlorobenzene p-Dichlorobenzene 3,3 -Dichlorobenzidine Dichlorodifluoromethane (Refrigerant 12)... 

Dibromoethane, 51 Dibutylamine, 51 Dibutylaminoethanol, 51 Di-tert-butyl-p-cresol, 51 Dibutyl phosphate, 51 Dibutyl phthalate (DBF), 51 Dicamba, 51 Dichloroacetic acid, 51 Dichlorobenzenes, 51 3,3 -Dichlorobenzidine and its salts, 52... 

Mere alteration of the strnctnre of the contaminant by biotransformation may not necessarily be acceptable. For example, although anaerobic dechlorination of PCBs is desirable, microbial redaction of 3,3 -dichlorobenzidine, which is an intermediate in the manufacture of dyes, produced benzidine that is both more toxic and more snsceptible to dissemination in the aqnatic phase (Nyman et al. 1997). 

Nyman MC, AK Nyman, LS Lee, LF Nies, ER Blatchley (1997) 3,3 -Dichlorobenzidine transformation processes in natural sediments. Environ Sci Technol 31 1068-1073. 

Emissions of dichlorobenzidine, chloroaniline, cuprous chloride and more during pigment production (17-20%)... 

Burton, D.J. and D.J. Fisher. 1990. Acute toxicity of cadmium, copper, zinc, ammonia, 3,3 -dichlorobenzidine, 2,6-dichloro-4-nitroaniline, methylene chloride, and 2,4,6-trichlorophenol to juvenile grass shrimp and killifish. Bull. Environ. Contam. Toxicol. 44 776-783. 

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