Nitrous Oxide


Chemical Symbol:          N2O
Shipping Name: Nitrous Oxide
Nitrous Oxide, Refrigerated Liquid
Classification: 2.2 (Nonflammable Gas)






Nitrous oxide at room temperature and atmospheric pressure is a colourless gas with a barely perceptible sweet odour and taste. It is non-flammable but will support combustion. At elevated temperatures, nitrous oxide decomposes into nitrogen and oxygen. Decomposition in the absence of catalysts is negligible at temperatures below 100oF. Nitrous oxide is moderately soluble in water, alcohol, and oils. Unlike some higher oxides of nitrogen, nitrous oxide does not affect the acidity of water solutions.





Nitrous oxide is available in medical, commercial, and high-purity grades. The medical grade is the most widely used. Manufacturers typically produce nitrous oxide for this use to specification published in the United States Pharmacopeias/National Formulary.





The major use of nitrous oxide is for anaesthesia and analgesia. It is also used for cryosurgery. Nitrous oxide also finds use as an oxidising gas semiconductor manufacturing, atomic absorption spectrophotometry, and as a fuel oxidant for racing vehicles.





Nitrous oxide’s primary physiological effect is central nervous system depression. At high concentration, anaesthetic levels can be obtained, but the low potency of nitrous oxide necessitates concomitant administration of other depressant drugs. Nitrous oxide has been associated with several side effects from long term exposure. The most strongly substantiated effect is neuropathy. Epidemiological studies also suggest fetotoxic effects and higher incidents of spontaneous abortion in exposed personnel.


Inhalation of nitrous oxide without the provision of a sufficient oxygen supply may be fatal or cause brain damage. Due to the concern over long term exposure effects, release of the product into general work areas should be minimised. NIOSH has recommended a maximum.





Nitrous oxide is non-corrosive and therefore may be used with any common, commercially available metals. Because of its oxidising action, however, all equipment being prepared to handle nitrous oxide, particularly at high pressures, must be free of oil, grease, and other readily combustible materials. Nitrous oxide may cause swelling of some elastomers.





Nitrous oxide will support combustion. It might be kept away from oil, grease, or any other readily combustible materials. Never permit oil, grease, or and other readily combustible substance to come in contact with cylinder or other equipment containing nitrous oxide.


Store and use nitrous oxide with adequate ventilation. Containers that become exposed to fire, including bulk storage tanks, could rupture violently if subjected to localised heating.


Requirements for nitrous oxide systems in hospitals and other health care facilities are found in NFPA 99, Standard for Health Care Facilities.


Nitrous oxide abuse has become a significant problem resulting in theft of cylinders and attempts to purchase for illegitimate and, in many cases, illegal use. It is recommended that nitrous oxide containers be stored in a secured area and policies be established to ensure sales are made only for legitimate uses.





Nitrous oxide is not harmful to the environment and can be released to the atmosphere, provided ventilation is adequate for protection of personnel in the immediate vicinity of the release point. Do not release in the vicinity of building air intakes.





Turn off ignition sources in the general area of the leak if possible. Nitrous oxide is non-flammable, but is an oxidiser that can cause or intensify fires. Evacuate the area to prevent asphyxiation. Use a self contained breathing apparatus (SCBA) to enter the area. Provide as much ventilation as possible. Avoid contact with liquid spills. Contact supplier for assistance.





Skin Contact - Contact with liquid nitrous oxide can freeze tissue. In case of frostbite, place frostbitten part in warm water, 100oF to 105oF (37.8oC to 40.6oC). If warm water is not available or it is impractical to use, wrap the affected part gently in blankets. Do not rub. Consult a physician.





Nitrous oxide is obtained in commercial quantities by the thermal decomposition of ammonium nitrate and by recovery from a by-product stream from adipic acid manufacturing processes.