4Nitrophenol [factsheet]

4-NITROPHENOL

Please Note: The main source of information for this fact sheet is the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for Nitrophenols. 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literature, and the Registry of Toxic Effects of Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.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

* No information is available on the levels of 4-nitrophenol in ambient air or in food, and 4-nitrophenol has not been detected in drinking water. (1)

* Occupational exposure to 4-nitrophenol may occur for those workers involved in the manufacture or use of 4-nitrophenol. (1)

Assessing Personal Exposure

* Methods exist for measuring 4-nitrophenol in the urine. However, these methods are not very useful unless the exposure was very recent. (1)

Health Hazard Information

Acute Effects:

* Acute (short-term) inhalation or ingestion of 4-nitrophenol in humans causes headaches, drowsiness, nausea, and cyanosis (blue color in lips, ears, and fingernails). Contact with the eyes causes irritation. (2)

* A study examining the acute effects of 4-nitrophenol from inhalation exposure in rats reported respiratory effects, an increase in methemoglobin, effects on the liver, and corneal opacity.(1)

* Tests involving acute exposure of animals, such as the LD₅₀ test in rats and mice, have shown 4-nitrophenol to have high toxicity from oral and dermal exposure. (1,3)

Chronic Effects (Noncancer):

* No information is available on the chronic (long-term) effects of nitrophenol in humans or animals from inhalation or oral exposure. (1)

* An animal study examining the chronic effects of 4-nitrophenol from dermal exposure reported no effects on the respiratory, cardiovascular, gastrointestinal, muscular, immune, and central nervous systems, or the liver and kidney. The only effects noted were dermal irritation consisting of erythema, scaling, scabbing, and cracking of the skin. (1)

* EPA has determined that there are inadequate data for the establishment of an RfC for 4-nitrophenol. (4)

* The RfD for 4-nitrophenol is under review by EPA. (4)

Reproductive/Developmental Effects:

* No information is available on the reproductive or developmental effects of 4-nitrophenol in humans.(1)

* One animal study reported no histological alterations in the testes and epididymides in mice exposed to 4-nitrophenol by inhalation, while in another study no changes were observed in the reproductive index of pregnant mice given 4-nitrophenol by gavage (placing the chemical experimentally in the stomach). (1)

Cancer Risk:

* No information is available on the carcinogenic effects of 4-nitrophenol in humans or animals. (1)

* EPA has not classified 4-nitrophenol for potential carcinogenicity. (4)

Physical Properties

* 4-Nitrophenol is a colorless to light yellow solid with no odor. (1)

* The chemical formula for 4-nitrophenol is C₆H₅NO₃, and the molecular weight is 139.11 g/mol. (1)

* The vapor pressure for 4-nitrophenol is 0.0003 mm Hg at 30 EC, and it has an octanol/water partition coefficient (Log K_ow) of 1.91. (1)

Uses

* 4-Nitrophenol is used to manufacture drugs, fungicides, and dyes and to darken leather. (1)

Health Data from Oral Exposure

Concentration (mg/kg/d)	Health numbers^a	Regulatory, advisory numbers^b	Reference
1,000,000.0
_ _ _ _ 100,000.0
_ _ _ _ 10,000.0
_ _ _ _ 1,000.0
_ _ _ _ 100.0	* LD₅₀ (dermal) (920 mg/kg) * LD₅₀ (mice) (470 mg/kg) * LD₅₀ (rats) (250 mg/kg)		3 3 3

LD₅₀ (Lethal Dose₅₀)CA calculated dose of a chemical in water to which exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population.

^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. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Nitrophenols (Draft). U.S. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 1990.

2. 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.

3. 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.

4. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 4-Nitrophenol. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.