2,4,6-Trichlorophenol
88-06-2
Hazard Summary
2,4,6-Trichlorophenol is no longer used in the United States and only very low levels have been detected in
ambient air. Limited information is available on the acute (short-term) and chronic (long-term) effects of
2,4,6-trichlorophenol in humans. The only available human study reported respiratory effects, such as
cough, chronic bronchitis, chest wheezing, altered pulmonary function, and pulmonary lesions from
chronic exposure to 2,4,6-trichlorophenol via inhalation. There are no studies available on the
reproductive, developmental, or carcinogenic effects of 2,4,6-trichlorophenol in humans. 2,4,6-
Trichlorophenol has been shown to be carcinogenic in animals, producing lymphomas, leukemia, and liver
cancer via oral exposure. EPA has classified 2,4,6-trichlorophenol as a Croup B2, probable human
carcinogen.
Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS) (3),
which contains information on the carcinogenic effects of 2,4,6-trichlorophenol including the unit cancer risk for
inhalation exposure, and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for
2,4,6-Trichlorophenol. (1)
Uses
	2,4,6-Trichlorophenol is no longer used in the United States. It was previously used as an antiseptic; a
pesticide for wood, leather, and glue preservation; and as an anti-mildew treatment. It was also used in
the manufacture of other chemicals. (1)
	Production of 2,4,6-trichlorophenol was discontinued in the United States in the 1 980s. (1)
Sources and Potential Exposure
	Very low levels of 2,4,6-trichlorophenol have been detected in air, with levels generally less than 0.001
parts per billion (ppb). (1)
	2,4,6-Trichlorophenol exposure may occur through drinking water or food. (1)
 Exposure to 2,4,6-trichlorophenol may occur through its use in pesticides, or wood, leather, or glue
preservatives which were produced before 2,4,6-trichlorophenol production was discontinued in the
1980s. (1)
Assessing Personal Exposure
	A test is available that can measure the amount of 2,4,6-trichlorophenol in the blood. (1)
Health Hazard Information
Acute Effects:
	No studies are available on the acute effects of 2,4,6-trichlorophenol in humans via inhalation or oral
exposure. (1)
	Tests involving acute exposure of rats have shown 2,4,6-trichlorophenol to have moderate acute
toxicity.(2)

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Chronic Effects (Noncancer):
	The only available chronic inhalation study in humans reported that occupational exposure to 2,4,6-
trichlorophenol was associated with respiratory effects such as cough, chronic bronchitis, chest wheezing,
altered pulmonary function, and pulmonary lesions. (1)
	Animal studies have reported effects on the blood (increased splenic hematopoesis) and liver (midzonal
vacuolization of hepatocytes and hepatic hyperplasia) from chronic oral exposure to 2,4,6-trichlorophenol,
while no effects on the cardiovascular system, gastrointestinal system, kidneys, skin, immune system, or
central nervous system were reported in these studies. (1)
	EPA has not established a Reference Concentration (RfC) or Reference Dose (RfD) for 2,4,6-trichlorophenol.
(3)
Reproductive/Develop mental Effects:
	No studies are available on the developmental or reproductive effects of 2,4,6-trichlorophenol in humans
from inhalation or oral exposure. (1)
	Animal studies have reported a transient reduction in the body weight of the offspring of rats exposed to
2,4,6-trichlorophenol orally, while no other developmental effects have been noted in animal studies. (1)
	Reduced mean litter size was observed in rats following maternal exposure to 2,4,6-trichlorophenol in the
drinking water, while no reproductive effects were observed in other animal studies via gavage (placing the
chemical experimentally in the stomach). (1)
Cancer Risk:
	No studies are available on the carcinogenic effects of 2,4,6-trichlorophenol in humans from inhalation or
oral exposure. (1,3)
	Oral exposure to 2,4,6-trichlorophenol in rats and mice resulted in an increased incidence of lymphomas
or leukemias and hepatocellular adenomas or carcinomas. (1,3)
	EPA has classified 2,4,6-trichlorophenol as a Group B2, probable human carcinogen. (3)
	EPA uses mathematical models, based on 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
-6	3 -1
unit risk estimate of 3.1 xlO (ug/m ) . EPA estimates that, if an individual were to continuously
3-4	3
breathe air containing 2,4,6-trichlorophenol at an average of 0.3 |jg/m (3x10 mg/m ) 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 3.0 |jg/m (3x10 mg/m ) would result in not greater than a ojie-in-hmndred
thousand increased chance of developing cancer, and air containing 30.0 |jg/m (3x10 mg/m ) would
result in not greater than a one-in-ten-thousand increased chance of developing cancer. For a detailed
discussion of confidence in the potency estimates, please see IRIS. (3)
	EPA has also calculated an oral unit risk factor of 3.1 x 1 0 (mq/U and an oral cancer slope factor of
0.01 1 (mg/kg/day) . (3)
Physical Properties
	2,4,6-Trichlorophenol is a yellow solid or flakes with a strong, sweet smell. (1)
	The odor threshold for 2,4,6-trichlorophenol is 0.0026 parts per million (ppm). (1)
	The chemical formula for 2,4,6-trichlorophenol is C H CI O, and its molecular weight is 1 97.46 g/mol. (1)
6 3 3
	The vapor pressure for 2,4,6-trichlorophenol is 0.01 2 mm Hg at 25 C, and it has a log octanol/water
partition coefficient (log K ) of 3.38. (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
3

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compound)/(24.45). For 2,4,6-tricMorophenol: 1 ppm = 8.1 mg/m . To convert concentrations in air from
|jg/m to mg/m : mg/m = (jjg/m ) x (1 mg/1,000 |jg).
Health Data from Inhalation Exposure
2,4,6-T rich lor ophenol
0.1
OjOI
w
E
"c
.s
i
5
0.001
OjOOOI
Health numbers11
Regulatory, advisory
numbers1*
-

-

EPA Cancer Risk Levef

fl-in-a-nnillbn excess

lifetinre risk =

00003 mg/m5)

Ref.



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.
c
These cancer risk estimates were derived from oral data and converted to provide the estimated inhalation risk.
Summary created in April 1 992, updated January 2000
References
1.	Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for 2,4,6-Trichlorophenol.
U.S. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 1 990.
2.	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.
3.	U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 2,4,6-Trichlorophenol.
National Center for Environmental Assessment, Office of Research and Development, Washington, DC.
1999.

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