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An Asphyxiant gas is a nontoxic or minimally toxic gas which reduces or displaces the normal oxygen concentration in breathing air. Breathing of oxygen-depleted air can lead to death by asphyxiation (suffocation). Because asphyxiant gases are relatively inert and odorless, their presence in high concentration may not be noticed, except in the case of carbon dioxide (hypercapnia). Toxic gases, by contrast, cause death by other mechanisms, such as competing with oxygen on the cellular level (e.g., carbon monoxide) or directly damaging the respiratory system (e.g., phosgene). Far smaller quantities of these are deadly. Notable examples of asphyxiant gases are nitrogen, argon, helium, butane and propane. Along with trace gases such as carbon dioxide and ozone, these compose 79% of Earth's atmosphere. The atmosphere is mostly harmless because the remaining 21% is O2. == Asphyxia hazard == (詳細はmines,〔Terazawa K, Takatori T, Tomii S, Nakano K. ''Methane asphyxia. Coal mine accident investigation of distribution of gas.'' Am J Forensic Med Pathol. 1985 Sep;6(3):211-4. PMID 3870672〕 submarines,〔(Discussion of the Kursk disaster and death on submarines )〕〔Kirk JC. ''Proposed minimum requirements for the operational characteristics and testing of submersible atmosphere monitoring and control units.'' Life Support Biosph Sci. 1998;5(3):287-94. PMID 11876195〕 refrigerators,〔Gill JR, Ely SF, Hua Z.''Environmental gas displacement: three accidental deaths in the workplace.'' Am J Forensic Med Pathol. 2002 Mar;23(1):26-30. PMID 11953489〕 or other confined spaces〔Sahli BP, Armstrong CW.''Confined space fatalities in Virginia.'' J Occup Med. 1992 Sep;34(9):910-7. PMID 1447597〕 * * Fire extinguisher systems that flood spaces with inert gases, such as computer data centers and sealed vaults〔 * * Large-scale natural release of gas, such as during the Lake Nyos disaster in which volcanically-released carbon dioxide killed 1,800 people.〔(BBC article on the Lake Nyos incident )〕 * * Release of helium boiled off by the energy released in a magnet quench such as the Large Hadron Collider or a magnetic resonance imaging machine. * * Climbing inside an inflatable balloon filled with helium〔Yoshitome K, Ishikawa T, Inagaki S, Yamamoto Y, Miyaishi S, Ishizu H. ''A case of suffocation by an advertising balloon filled with pure helium gas.'' Acta Med Okayama. 2002 Feb;56(1):53-5. PMID 11873946〕 * Direct administration of gas * * Exclusive administration, such as inhaling the contents of a balloon filled with helium〔http://www.ci.medford.or.us/News.asp?NewsID=3656〕 * * Inadvertent administration of asphyxiant gas in respirators〔(OSHA article on asphyxiant gases accidentally fed into respirators )〕 * * Use in suicide〔Gallagher KE, Smith DM, Mellen PF. ''Suicidal asphyxiation by using pure helium gas: case report, review, and discussion of the influence of the internet.'' Am J Forensic Med Pathol. 2003 Dec;24(4):361-3. PMID 14634476〕〔Gilson T, Parks BO, Porterfield CM. ''Suicide with inert gases: addendum to Final Exit.'' Am J Forensic Med Pathol. 2003 Sep;24(3):306-8. PMID 12960671〕 and erotic asphyxiation〔Shields LB, Hunsaker DM, Hunsaker JC 3rd, Wetli CV, Hutchins KD, Holmes RM. ''Atypical autoerotic death: part II.'' Am J Forensic Med Pathol. 2005 Mar;26(1):53-62. PMID 15725777〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Asphyxiant gas」の詳細全文を読む スポンサード リンク
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