1,2Diphenylhydrazine [factsheet]

1,2-DIPHENYLHYDRAZINE

Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS), which contains information on the carcinogenic effects of 1,2-Diphenylhydrazine including the unit cancer risk for inhalation exposure, and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for 1,2-Diphenylhydrazine. Other secondary sources include 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literature, and the Registry of Toxic Effects of Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.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

* Human exposure to 1,2-diphenylhydrazine appears to be primarily occupational; however, the number of workers potentially exposed has declined because dye manufacturers in the United States no longer produce benzidine-based dyes. (1)

Assessing Personal Exposure

* There is no test currently available to determine whether or not exposure to 1,2-diphenylhydrazine has occurred. (1)

Health Hazard Information

Acute Effects:

* No information is available on the acute (short-term) effects of 1,2-diphenylhydrazine in humans or animals.

Chronic Effects (Noncancer):

* No information is available on the chronic (long-term) effects of 1,2-diphenylhydrazine in humans.

* Degenerative alterations in the liver and depressed weight gain have been observed in rats and mice chronically exposed to 1,2-diphenylhydrazine in their diet. (1,2)

* Intestinal hemorrhage in mice and stomach hyperkeratosis and acanthosis in rats has been observed when the rodents were chronically exposed to 1,2-diphenylhydrazine in their diet. (1,2)

* Chronic oral administration of 1,2-diphenylhydrazine produced interstitial inflammation of the lungs in rats. (1)

* EPA has not established an RfC or an RfD for 1,2-diphenylhydrazine. (3)

Reproductive/Developmental Effects:

* No information is available on the reproductive or developmental effects of 1,2-diphenylhydrazine in humans.

* In one study, no effects on reproductive organs were found in rats and mice exposed via ingestion. (1)

Cancer Risk:

* No information is available on the carcinogenic effects of 1,2-diphenylhydrazine in humans.

* Hepatocellular carcinomas have been observed in rats and mice exposed to 1,2-diphenylhydrazine in their diet. (1,3)

* In dermally exposed mice, tumors of the lung and liver were reported. (1,3)

* EPA has classified 1,2-diphenylhydrazine as a Group B2, probable human carcinogen. (3)

* EPA uses mathematical models, based on human and animal studies, to estimate the probability of a person developing cancer from breathing air containing a specified concentration of a chemical. EPA calculated an inhalation unit risk estimate of 2.2 H 10^-4 (Fg/m³)^-1. EPA estimates that, if an individual were to breathe air containing 1,2-diphenylhydrazine at 0.005 m g/m³* over his or her entire lifetime, that person would theoretically have no more than a one-in-a-million increased chance of developing cancer as a direct result of breathing air containing this chemical. Similarly, EPA estimates that breathing air containing 0.05 m g/m³ would result in not greater than a one-in-a-hundred thousand increased chance of developing cancer, and air containing 0.5 m g/m³ would result in not greater than a one-in-ten thousand increased chance of developing cancer. (3)

* 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 1,2-diphenylhydrazine in the nonthreshold category. The 1/ED₁₀ value is 4.3 per (mg/kg)/d and this would place it in the medium category under Superfund's ranking for carcinogenic hazard. (4)

Physical Properties

* The chemical formula for 1,2-diphenylhydrazine is C₁₂H₁₂N₂, and its molecular weight is 184.24 g/mol. (1)

* 1,2-Diphenylhydrazine occurs as a white crystalline solid that dissolves only slightly in water. (1)

* The odor threshold for 1,2-diphenylhydrazine has not been established. (1)

* The vapor pressure for 1,2-diphenylhydrazine is 2.6 H 10^-5 mm Hg at 25 EC, and its log octanol/water partition coefficient (log K_ow) is 2.94. (1)

Uses

* 1,2-Diphenylhydrazine is no longer produced in the United States. (1)

* 1,2-Diphenylhydrazine is used as a starting material in the production of benzidine. Benzidine was previously used to manufacture benzidine-based dyes. (1)

* 1,2-Diphenylhydrazine is also used in the production of anti-inflammatory drugs. (1)

Note: There are very few health numbers or regulatory/advisory numbers for 1,2-diphenylhydrazine; thus, a graph has not been prepared for this compound.

References

1. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for 1,2-Diphenylhydrazine. U.S. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 1990.

2. U.S. Environmental Protection Agency. Health Effects Assessment for 1,2-Diphenylhydrazine. EPA/600/8-88/033. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1988.

3. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 1,2-Diphenylhydrazine. 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.