Agent Name

C.I. Direct Blue 6

CAS Number




Major Category



Airedale Blue 2BD; Aizen Direct Blue 2BH; Amanil Blue 2BX; Atlantic Blue 2B; Atul Direct Blue 2B; Azocard Blue 2B; Azomine Blue 2B; Belamine Blue 2B; Bencidal Blue 2B; Benzanil Blue 2B; Benzo Blue BBA-CF; Benzo Blue BBN-CF; Benzo Blue GS; Blue 2B; Blue 2B salt; Brasilamina Blue 2B; C.I. 22610; C.I. Direct Blue 6, tetrasodium salt; Calcomine Blue 2B; Chloramine Blue 2B; Chlorazol Blue B; Chlorazol Blue BP; Chrome Leather Blue 2B; Cresotine Blue 2B; Diacotton Blue BB; Diamine Blue; Diamine Blue 2B; Diamine Blue BB; Diaphtamine Blue BB; Diazine Blue 2B; Diazol Blue 2B; Diphenyl Blue 2B; Diphenyl Blue KF; Diphenyl Blue M2B; Direct Blue 2B; Direct Blue 2BA; Direct Blue 6; Direct Blue 6 (technical grade); Direct Blue A; Direct Blue BB; Direct Blue GS; Direct Blue K; Direct Blue M2B; Direct Sky Blue K; Enianil Blue 2BN; Fenamin Blue 2B; Fixanol Blue 2B; Hispamin Blue 2B; Indigo Blue 2B; Kayaku Direct; Kayaku Direct Blue BB; Mitsui Direct Blue 2BN; Modr Prima 6 [Czech]; Naphtamine Blue 2B; Niagara Blue 2B; Nippon Blue BB; Paramine Blue 2B; Phenamine Blue BB; Pheno Blue 2B; Pontamine Blue BB; Sodium diphenyl-4,4'-bis-azo-2"-8"-amino-1"-naphthol-3",6"-disulphonate; Tertrodirect Blue 2B; Vondacel Blue 2B; 2,7-Naphthalenedisulfonic acid, 3,3'-((1,1'-biphenyl)-4,4'-diylbis(azo))bis(5-amino-4-hydroxy-, tetrasodium salt; [ChemIDplus]


Benzidine Dyes


Blue violet solid; [HSDB]


Used in dyes (silk, wool, cotton, nylon, leather, and paper), biological stains, writing inks, and hair dyes; [HSDB] In a NIOSH survey of US industries in 1972-1974, workers were exposed to Direct Black 38, Direct Brown 95, and Direct Blue 6 (benzidine-based dyes) in the textiles, paper, and leather industries; [Zenz, p. 709]


Caused liver adenomas and carcinomas in high-dose feeding studies of rats for 13 weeks; Commercial substance is a reaction product, not a single substance; [HSDB] One of the azo dyes metabolized to benzidine--known to be a human carcinogen; [NTP] May be absorbed through the skin; [CAMEO] May cause cancer; Possible reproductive hazard; May cause irritation; Toxic by ingestion; Oral LD50 (rat) = 8760 mg/kg; [MSDSonline] See "Benzidine."

Reference Link

IARC 2012: Dyes Metabolized to Benzidine

Adverse Effects

Hepatotoxin, Secondary

IARC Carcinogen

Known Carcinogen

NTP Carcinogen

Human Carcinogen

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information


Chemical Information

Search ChemIDplus

Biomedical References

Search PubMed

Related Information in HazMap

Occupational diseases associated with exposure to this agent:


Industrial Processes with risk of exposure: