OSHA Permissible Exposure Limit (PEL) for Construction Industry:29 CFR 1926.55 Appendix A -- Simple asphyxiants. The limiting factor is the available oxygen which shall be at least 19.5% and be within the requirements addressing explosion in part 1926.
OSHA Permissible Exposure Limit (PEL) for Maritime:29 CFR 1915.1000 Table Z-Shipyards -- Simple asphyxiants. The limiting factor is the available oxygen which shall be at least 18 percent and be within the requirements addressing explosion in subpart B of part 1915.
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 50 ppm, 90 mg/m3 TWA; Appendix A4 - Not Classifiable as a Human Carcinogen
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 25 ppm, 46 mg/m3 TWA over the time exposed. [Note: REL for exposure to waste anesthetic gas.]
International Agency for Research on Cancer (IARC) carcinogenic classification: Anaesthetics, volatile – Group 3, not classifiable as to its carcinogenicity to humans [1 MB, PDF]
Potential symptoms: Dyspnea; euphoria, drowsiness; headache; asphyxia; reproductive effects; frostbite (from contact with liquid), lowering of consciousness.
Health Effects: Reproductive Hazard (Male and Female) (HE5); CNS effects (HE7); Asphyxiant (HE17); Bone marrow depression (HE12).
Affected organs: Respiratory system, CNS, peripheral nervous system, reproductive system
Occupational exposure to nitrous oxide is primarily via its use in anesthesia and analgesia by health care personnel.
Nitrous oxide is a drug of abuse by inhalation and has caused a number of deaths from asphyxia.
Long-term exposure to nitrous oxide can result in some symptoms of pernicious anemia: megaloblastic bone-marrow depression or peripheral and central neuropathy (tingling, numbness, impairment of equilibrium, difficulty in thinking clearly).
These symptoms result from the inhibition of methionine synthase by the nitrous oxide-induced inactivation of the reduced form of vitamin B12.
Date Last Revised: 05/30/2007
Literature Basis:
NIOSH Pocket Guide to Chemical Hazards: Nitrous oxide.
International Chemical Safety Cards (WHO/IPCS/ILO): Nitrous oxide.
Pohanish, R.P. (editor): Nitrous Oxide. In, Sittig’s Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 1748-1749.
Rowland, A.S., Baird, D.D., Shore, D.L., Weinberg, C.R., Savitz, D.A. and Wilcox, A.J.: Nitrous oxide and spontaneous abortion in female dental assistants. Am. J. Epidemiol.141(6): 531-538, 1995.
Suruda, A.J. and McGlothlin, J.D.: Fatal abuse of nitrous oxide in the workplace. J. Occup. Med.32(8): 682-684, 1990.
Weimann, J.: Toxicity of nitrous oxide. Best Pract. Res. Clin. Anaesthesiol.17(1): 47-61, 2003.
sampling media: VAPOR-TRAK Nitrous Oxide Monitor
maximum time: 16 Hours minimum time: 15 Minutes
current analytical method: Infrared; IL33
method reference: Follow Manufacturer's Instruction Sheet. SLTC has not evaluated this product.
method classification: Not Validated
note: Analysis performed by manufacturer of badge. Badges are sent to the OSHA Technical Center. SLTC has not evaluated this product. CSHO's should consult OSHA instruction CPL 2-2.60 prior to taking any samples where exposure to bloodborne pathogens could occur.
sampling media: Five Layer Aluminized Gas Sampling Bag (5 liter)
maximum volume: 5 Liters maximum flow rate: 0.05 L/min
current analytical method: Infrared; IL52
method reference: OSHA In-House File
method classification: Not Validated
Wisconsin Occupational Health Laboratory (WOHL) Method:
sampling media: Evacuated Cans - Back Filled with Nitrogen (Hold button down for a full 10 seconds)
maximum volume: 120 mLiters
current analytical method: Mass Spectrometry; GC/MS
method reference: WOHL In-House File
method classification: Not Validated
note: Call Wisconsin Occupational Health Laboratory (WOHL) for instructions and evacuated cans.
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