3,3'Dimethoxybenzidine [factsheet]

3,3'-DIMETHYLBENZIDINE

Please Note: The main sources of information for this fact sheet are the Hazardous Substances Data Bank (HSDB), a database of summaries of peer-reviewed literature, and the Registry of Toxic Effects of Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.

Environmental/Occupational Exposure

* Occupational exposure to 3,3'-dimethylbenzidine may occur for those workers in dye manufacturing and processing plants. (1)

* Dermal exposure to the general population may occur from the use of packaged dyes and pigments for home use derived from 3,3'-dimethylbenzidine. (1)

Assessing Personal Exposure

* No information is available on the measurement of personal exposure to 3,3'-dimethylbenzidine.

Health Hazard Information

Acute Effects:

* Acute (short-term) exposure to high levels of 3,3'-dimethylbenzidine in humans may irritate the nose and throat. (2)

* No information is available on the acute effects of 3,3'-dimethylbenzidine in animals.

Chronic Effects (Noncancer):

* No information is available on the chronic (long-term) effects of 3,3'-dimethylbenzidine in humans or animals.

* EPA has not established an RfD for 3,3'-dimethylbenzidine. (3)

* EPA has determined that there are inadequate data for the establishment of an RfC for 3,3'-dimethylbenzidine. (3)

Reproductive/Developmental Effects:

* No information is available on the reproductive or developmental effects of 3,3'-dimethylbenzidine in humans or animals.

Cancer Risk:

* No information is available on the carcinogenic effects of 3,3'-dimethylbenzidine in humans.

* Animal studies indicate that oral exposure to 3,3'-dimethylbenzidine results in an increased incidence of tumors of the intestine, skin, liver, lung, and other organs. (1,2)

* EPA has classified 3,3'-dimethylbenzidine as a Group B2, probable human carcinogen. (4)

* EPA's Office of Air Quality Planning and Standards, for a hazard ranking under Section 112(g) of the Clean Air Act Amendments, has ranked 3,3'-dimethylbenzidine in the nonthreshold category. The 1/ED₁₀ value is 27 per (mg/kg)/d and this would place it in the medium category under Superfund's ranking for carcinogenic hazard. (4)

Physical Properties

* 3,3'-dimethylbenzidine is a white to red colored crystalline solid. (2)

* The chemical formula for 3,3'-dimethylbenzidine is C₁₄H₁₆N₂, and the molecular weight is 212.3 g/mol. (5)

* The vapor pressure for 3,3'-dimethylbenzidine is 1.7 H 10^-4 mm Hg at 25 EC, and it has a log octanol/water partition coefficient (Log K_ow) of 4.59. (5)

Uses

* 3,3'-dimethylbenzidine is used as an intermediate for the production of dyes and pigments. (6)

Health Data from Inhalation Exposure

Concentration (mg/m³)	Health numbers^a	Regulatory, advisory numbers^b	Reference
1,000,000.0
_ _ _ _ 100,000.0
_ _ _ _ 10,000.0
_ _ _ _ 1,000.0
_ _ _ _ 100.0
_ _ _ _ 10.0
_ _ _ _ 1.0
_ _ _ _ 0.1		* NIOSH REL (0.02 mg/m³)	2

NIOSH RELCNational Institute of Occupational Safety and Health recommended exposure limit; NIOSH-recommended exposure limit for an 8- or 10-h time-weighted-average exposure and/or ceiling.

^a Health numbers are toxicological numbers from animal testing or risk assessment values developed by EPA.

^b Regulatory numbers are values that have been incorporated in Government regulations, while advisory numbers are nonregulatory values provided by the Government or other groups as advice.

References

1. U.S. Department of Health and Human Services. Hazardous Substances Data Bank (HSDB, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.

2. New Jersey Department of Health. Hazardous Substance Fact Sheet on 3,3'-Dimethylbenzidine. New Jersey Department of Health, Trenton, NJ. 1986.

3. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 3,3'-Dimethylbenzidine. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.

4. U.S. Environmental Protection Agency. Technical Background Document to Support Rulemaking Pursuant to the Clean Air ActCSection 112(g). Ranking of Pollutants with Respect to Hazard to Human Health. EPAB450/3-92-010. Emissions Standards Division, Office of Air Quality Planning and Standards, Research Triangle Park, NC. 1994.

5. U.S. Environmental Protection Agency. Assessment Tools for the Evaluation of Risk (ASTER, online database). Environmental Research Laboratory, Duluth, MN. 1993.

6. U.S. Department of Health and Human Services. Registry of Toxic Effects of Chemical Substances (RTECS, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.