N-Nitrosodimethylamine
62-75-9
Hazard Summary
Individuals may be exposed to low levels of N-nitrosodimethylamine in occupational settings, through the
ingestion of food that contains it (e.g., cured meat products and smoked fish), and from breathing cigarette
smoke. Acute (short-term) exposure to N-nitrosodimethylamine may damage the liver in humans, with
symptoms that include nausea, vomiting, headaches, and malaise. Chronic (long-term) exposure of
humans toN-nitrosodimethylamine may cause liver damage and low platelet counts. Severe liver damage
has been observed in animals. Limited human data are available on the carcinogenic effects of N-
nitrosodimethylamine. Animal studies have suggested that chronic ingestion and inhalation of N-
nitrosodimethylamine may cause an increase in liver tumors and other types of tumors. EPA has
classified N-nitrosodimethylamine as a Group B2, probable human carcinogen.
Please Note: The main sources of information for this fact sheet are EPA's Integrated Risk Information System (IRIS)
(5), which contains information on the carcinogenic effects of N-nitrosodimethylamine including the unit cancer risk
for inhalation exposure, the Hazardous Substances Data Bank (HSDB) (1), a database of summaries of peer-reviewed
literature, the International Agency for Research on Cancer (IARC) monographs on chemicals carcinogenic to
humans (3), and the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for N-
Nitrosodimethylamine. (8)
Uses
s N-Nitrosodimethylamine is primarily used as a research chemical. (7,8)
s N-Nitrosodimethylamine has been used as an antioxidant, as an additive for lubricants, and as a softener
of copolymers. (1,2,5,8)
s N-Nitrosodimethylamine was formerly used in the production of rocket fuels. (1,2,5)
Sources and Potential Exposure
a Individuals are most likely to be exposed to N-nitrosodimethylamine in occupational settings such as in the
rubber, tannery, fish processing, dye, and surfactant industries. (1,8)
a Humans may be exposed to low levels of N-nitrosodimethylamine through the ingestion of food that
contains it, such as cured meat products and smoked fish. Other exposures to the chemical may be from
drinking contaminated water and from breathing cigarette smoke and contaminated ambient air. (1,2,8)
Assessing Personal Exposure
¦ N-Nitrosodimethylamine can be detected in blood and urine by a test. (8)
Health Hazard Information
Acute Effects:
a Acute exposure to N-nitrosodimethylamine may cause liver damage in humans, with symptoms that
include nausea, vomiting, headaches, and malaise. (1,3-5,8)

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s Hematological and severe liver effects (hemorrhagic necrosis) were reported in animals acutely exposed via
inhalation and ingestion. (8)
s Tests involving acute exposure of rats, mice, and hamsters have demonstrated that N-
nitrosodimethylamine has high to extreme acute toxicity from inhalation or oral exposure. (6)
Chronic Effects (Noncancer):
a Chronic exposure of humans to N-nitrosodimethylamine may cause liver damage (jaundice and swelling)
and low platelet counts. (1,4,5,8)
a Chronic oral exposure has resulted in severe liver damage in animals. (8)
a EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for N-
nitrosodimethylamine. (5)
Reproductive/Developmental Effects:
a No information is available on the reproductive or developmental effects of N-nitrosodimethylamine in
humans.
a In a study of rats exposed to N-nitrosodimethylamine by injection, increased fetal mortality was observed
but no birth defects were noted. (3)
a N-Nitrosodimethylamine, when administered to pregnant rats, mice, and hamsters by several routes, has
been shown to cause cancer in the offspring. (1,5)
Cancer Risk:
a Data from human studies are of limited use because human exposure to nitrosamines generally results from
contact with mixtures of these compounds. (5)
a N-Nitrosodimethylamine has been found to be carcinogenic in a number of animal species, inducing tumors
in various organs and by various routes of exposure. Increased incidences of liver, kidney, and lung tumors
have been observed in rats and mice that inhaled N-nitrosodimethylamine. Liver tumors have also been
observed in orally exposed rats, mice, and hamsters. (1,3-5,7,8)
¦ EPA has classified N-nitrosodimethylamine as a Group B2, probable human carcinogen. (5)
• 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 1.4 x 10 (|jg/m ) . EPA estimates that, if an individual were
to continuously breathe air containing N-nitrosodimethylamine at an average of 0.00007 micrograms per
3-8	3
cubic meter (jjg/m ) (7 x 1 0 milligrams per cubic meter, 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 an average of 0.0007 |jg/m (7x10 mg/m ) would result in not greater than a one-in-a-
3
hundred thousand increased chance of developing cancer, and air containing an average of 0.007 |jg/m (7
-6	3
x 1 0 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. (5)
a EPA has calculated an oral cancer slope factor of 51 (mg/kg/d) .(5)
Physical Properties
a The chemical formula for N-nitrosodimethylamine is C H N O, and its molecular weight is 74.08 g/mol.
2 6 2
(2,8)
a N-Nitrosodimethylamine is a yellow, oily liquid that is very soluble in water. (1,2,7)
a N-Nitrosodimethylamine has a faint characteristic odor; the odor threshold has not been established. (5)
a The log octanol/water partition coefficient (log K ) is 0.57 and the vapor pressure is 2.7 mm Hg at 20°
ow

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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 N-nitrosodimethylamine: 1 ppm = 3.03 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
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Regulatory, adviso ry
numbers'*
Health numbers
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Ref.
LC (Lethal Concentration )—A calculated concentration of a chemical in air to which exposure for a specific
50	50
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.
References
Summary created in April 1992, updated in January 2000
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. 1 993.
2.	The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals. 1 1 th ed. Ed. S. Budavari. Merck and
Co. Inc., Rahway, NJ. 1989.
3.	International Agency for Research on Cancer (IARC). IARC Monographs on the Evaluation of the
Carcinogenic Risk of Chemicals to Humans: Some N-Nitroso Compounds. Volume 1 7. World Health
Organization, Lyon. 1978.
4.	M. Sittig. Handbook of Toxic and Hazardous Chemicals and Carcinogens. 2nd ed. Noyes Publications. Park
Ridge, NJ. 1985.
5.	U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on N-
Nitrosodimethylamine. National Center for Environmental Assessment, Office of Research and

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Development, Washington, DC. 1999.
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.
7.	U.S. Department of Health and Human Services (DHHS).The 8th Report on Carcinogens. 1 998
Summary. Public Health Service, National Toxicology Program. 1998.
8.	Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for N-
Nitrosodimethylamine. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA.
1989.

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