4-Nitrophenol
100-02-7
Hazard Summary
4-Nitrophenol is used to manufacture drugs, fungicides, insecticides, and dyes and to darken leather.
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 eyes causes irritation in
humans. No information is available on the chronic (long-term) effects of 4-nitrophenol in humans or
animals from inhalation or oral exposure. No information is available on the reproductive, developmental,
or carcinogenic effects of 4-nitrophenol in humans. EPA has not classified 4-nitrophenol for potential
carcinogenicity.
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. (1)
Uses
	4-Nitrophenol is used to manufacture drugs (e.g., acetaminophen), fungicides, methyl and ethyl parathion
insecticides, and dyes and to darken leather. (1)
Sources and Potential 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 inhalation or ingestion of 4-nitrophenol in humans causes headaches, drowsiness, nausea, and
cyanosis. Contact with the eyes causes irritation. (2)
	A study examining the acute effects of 4-nitrophenol from inhalation exposure in rats reported an increase
in methemoglobin and corneal opacity. (1)
	Tests involving acute exposure of 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 effects of 4-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

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liver and kidney. The only effects noted were dermal irritation consisting of erythema, scaling, scabbing,
and cracking of the skin. (1)
	EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for 4-nitrophenol. (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. (1)
	There was no evidence of carcinogenic activity in mice dermally exposed to 4-nitrophenol for 1 8 months in
a National Toxicology Program (NTP) study. (5)
	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 C H NO , and the molecular weight is 1 39.1 1 g/mol. (1)
6 5 3
	The vapor pressure for 4-nitrophenol is 0.0003 mm Hg at 30 C, and it has a log octanol/water partition
coefficient (log K ) of 1.91. (1)
ow
Conversion Factors:
3	3
To convert concentrations in air (at 2 5 C) from ppm to mg/m : mg/m = (ppm) x (molecular weight of the
compound)/(24.45). For 4-nitrophenol: 1 ppm = 5.7 mg/m .
Health Data from Oral Exposure

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4-Nitrophenol
%
E
I
a
w
c
3
10000
1000
100
Regulatory, advisory
numbers'*
Health numbers
LD (terms 020 mg/k(J
LD JmioeJ {470 mg/kg)
LD (rats) (250 rngfkg)
EeL
EeL
10
(Lethal Dose )A 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.
The health values cited in this factsheet were obtained in December 1 999.
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.
Summary created in April 1 992, updated January 2000
References
1.	Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Nitrophenols (Draft).
Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 1 990.
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. 1 993.
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 p-Nitrophenol. National
Center for Environmental Assessment, Office of Research and Development, Washington, DC. 1 999.
5.	National Toxicology Program. Toxicology and Carcinogenesis Studies of p-Nitrophenol (CAS No. 1 00-02-
7) in Swiss Webster Mice (Dermal Studies). TR-417. 1993.

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