Technology Transfer Network - Air Toxics Web Site
Hazard Summary-Created in April 1992; Revised in January 2000
The major source of exposure to diazomethane is occupational. Diazomethane
is a strong respiratory irritant. Acute (short-term) inhalation
exposure of humans to diazomethane may cause irritation of the eyes, cough,
wheezing, asthmatic symptoms, pulmonary edema, pneumonia, dizziness, weakness,
headache, and chest pains. No information is available on the chronic
(long-term), reproductive, developmental, or carcinogenic effects of diazomethane
in humans. Increased incidences of lung tumors have been observed
in rats and mice exposed to diazomethane by inhalation and in dermally
exposed mice. EPA has not classified diazomethane with respect to
its potential carcinogenicity.
- Diazomethane is used as a methylating agent for acidic compounds such as carboxylic acids, phenols, and enols. (1,2,4)
Sources and Potential Exposure
- Humans may be occupationally exposed to diazomethane in the workplace. (1)
Assessing Personal Exposure
- No information was located regarding the measurement of personal exposure to diazomethane.
Health Hazard InformationAcute Effects:
- Diazomethane is a strong respiratory irritant. Acute inhalation exposure of humans to diazomethane may cause irritation of the eyes, cough, wheezing, asthmatic symptoms, pulmonary edema, pneumonia, dizziness, weakness, headache, chest pains, fever, moderate cyanosis, malaise, tremors, liver enlargement, hypersensitivity, and shock. (1-5)
- Severe respiratory tract irritation, hemorrhagic emphysema, pulmonary edema, and bronchopneumonia have been observed in animals acutely exposed by inhalation. (2-4)
- Acute animal tests in cats have demonstrated diazomethane to have high acute toxicity by inhalation. (6)
- No information is available on the chronic effects of diazomethane in humans or animals.
- EPA has not established a Reference Concentration (RfC) or a Reference Dose (RfD) for diazomethane. (7)
- No information is available on the reproductive or developmental effects of diazomethane in humans or animals.
- No information is available on the carcinogenic effects of diazomethane in humans.
- Increased incidences of pulmonary adenomas have been observed in rats and mice exposed to diazomethane by inhalation and in dermally exposed mice. (2,3,5)
- EPA has not classified diazomethane with respect to its potential carcinogenicity. (7)
- The International Agency for Research on Cancer (IARC) has classified diazomethane as a Group 3, not classifiable as to its carcinogenicity to humans. (2)
- The chemical formula for diazomethane is CH2N2, and its molecular weight is 42.04 g/mol. (4)
- Diazomethane occurs as a very toxic, explosive yellow gas. (2-5)
- Diazomethane has a musty odor; the odor threshold has not been established. (2)
To convert concentrations in air (at 25°C) from ppm to mg/m3: mg/m3 = (ppm) × (molecular weight of the compound)/(24.45). For diazomethane: 1 ppm = 1.72 mg/m3.
Health Data from Inhalation Exposure
ACGIH TLV--American Conference of Governmental and Industrial
Hygienists' threshold limit value expressed as a time-weighted average;
the concentration of a substance to which most workers can be exposed
without adverse effects.
LC50 (Lethal Concentration50)--A calculated concentration of a chemical in air to which exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population.
NIOSH IDLH--National Institute of Occupational Safety and Health's immediately dangerous to life or health limit; NIOSH recommended exposure limit to ensure that a worker can escape from an exposure condition that is likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from the environment.
NIOSH REL--NIOSH's recommended exposure limit; NIOSH-recommended exposure limit for an 8- or 10-h time-weighted-average exposure and/or ceiling.
OSHA PEL--Occupational Safety and Health Administration's permissible exposure limit expressed as a time-weighted average; the concentration of a substance to which most workers can be exposed without adverse effect averaged over a normal 8-h workday or a 40-h workweek.
The health and regulatory values cited in this factsheet were obtained
in December 1999.
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. OSHA numbers are regulatory, whereas NIOSH and ACGIH numbers are advisory.
- M. Sittig. Handbook of Toxic and Hazardous Chemicals and Carcinogens. 2nd ed. Noyes Publications, Park Ridge, NJ. 1985.
- 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.
- International Agency for Research on Cancer (IARC). IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Man: Some Anti-Thyroid and Related Substances, Nitrofurans and Industrial Chemicals. Volume 7. World Health Organization, Lyon. 1974.
- The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals. 11th ed. Ed. S. Budavari. Merck and Co. Inc., Rahway, NJ. 1989.
- G.D. Clayton and F.E. Clayton, Eds. Patty's Industrial Hygiene and Toxicology. Volume IIA. 3rd revised ed. John Wiley & Sons, New York. 1981.
- 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.
- U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on Diazomethane. National Center for Environmental Assessment, Office of Research and Development, Washington, DC. 1999.
- American Conference of Governmental Industrial Hygienists (ACGIH). 1999 TLVs and BEIs. Threshold Limit Values for Chemical Substances and Physical Agents. Biological Exposure Indices. Cincinnati, OH. 1999.
- National Institute for Occupational Safety and Health (NIOSH). Pocket Guide to Chemical Hazards. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention. Cincinnati, OH. 1997.
- Occupational Safety and Health Administration (OSHA). Occupational Safety and Health Standards, Toxic and Hazardous Substances. Code of Federal Regulations. 29 CFR 1910.1000. 1998.