Simple asphyxiates

Paraffins. Methane and ethane are simple asphyxiants, whereas the higher homologues are central nervous system depressants. Liquid paraffins can remove oil from exposed skin and cause dermatitis or pneumonia in lung tissue. Generally, paraffins are the least toxic class of hydrocarbons. 

Simple asphyxiant value shown is 10% of the lower flammable limit (LFL). 

Inerts Cases Simple asphyxiants Argon methane hydrogen nitrogen helium. Particulates e.g. cement, calcium carbonate. 

Simple asphyxiant. Some gases and vapours present at high concentrations act as asphyxiants by reducing the oxygen content of air. Many of these are odourless and colourless. Many also pose a fire or explosion risk, often at values below which asphyxiation can occur. (Although capable of asphyxiation, they are not considered to be substances hazardous to health under COSHH.)... 

Aeetylene is a simple asphyxiant and anaestlietie. Pure aeetylene is a eolourless, highly flammable gas with an ethereal odour. Material of eommereial purity has an odour of garlie due to the presenee of impurities sueh as phosphine. Its physieal properties are shown in Table 9.4. Aeetylene, whieh eondenses to a white solid subliming at -83°C, is soluble in its own volume of water but highly soluble in aeetone. 

Propane has a eharaeteristie natural gas odour and is basieally insoluble in water. It is a simple asphyxiant but at high eoneentrations has an anaesthetie effeet. The TLV is 2500 ppm. It is usually shipped in low-pressure eylinders as liquefied gas under its own vapour pressure of ea 109 psig at 21°C. Its pressure/temperature profile is given in Figure 9.7. 

Health Hazards Information - Recommended Persoruil Protective Equipment Self-contained breathing apparatus for high vapor concentrations Symptoms Following Exposure In high vapor concentrations, can act as simple asphyxiant. Liquid causes severe frostbite General Treatment for Exposure Remove from Exposure, support respiration Toxicity by Inhalation (Threshold Umit Value) Not pertinent Short-Term Exposure Limits Not pertinent Toxicity by Ingestion Not pertinent Late Toxicity None Vapor (Gas) Irritant Characteristics Vapors are nonirritating to the eyes and throat Uquid or Solid Irritant Characteristics Not pertinent appreciable hazard. Practically harmless to the skin because is very volatile and evaporates quickly Odor Threshold 899 ppm. 

Asphyxiant Simple asphyxiants are inert gases which deplete the oxygen supply in the breathing air to below the critical value of J8% by volume, such as gaseous fuels or nitrogen. Chemical asphyxiants, such as carbon monoxide and hydrogen cyanide, have a direct biological effect. 

Simple asphyxiant Substance that displaces air, producing an oxygen-deficient at-mosphete. 

Asphyxiation and Toxicity Hazards An asphyxiant is a chemical (either a gas or a vapor) that can cause death or unconsciousness by suffocation (BP, Hazards of Nitrogen and Catalyst Handling, 2003). A simple asphyxiant is a chemical, such as N2, He, or Ar, whose effects are caused by the displacement of 02 in air, reducing the 02 concentration below its normal value of approximately 21 vol %. The physiological effects of oxygen concentration reduction by simple asphyxiants are illustrated in Table 23-18 (BP, Hazards of Nitrogen and Catalyst Handling, 2003). 

Note that C02 acts as neither a simple asphyxiant (like N2) nor a chemical asphyxiant (like CO). The normal concentration of C02 in air is approximately 300 ppm (0.03 vol %). Table 23-19 (Air Products, Carbon Dioxide, Safetygram 18, 1998) illustrates that exposure to air diluted by 5 vol % C02 (yielding an oxygen concentration of 21 x 0.95, or approximately 20 vol %) prompts physiological effects that are more severe than those inferred from Table 23-18 for dilution by the same amount of nitrogen. 

Toxicology. Carbon dioxide usually is considered a simple asphyxiant, although it also is... 

Toxieology. Ethane is considered to be toxi-cologically inert and is classified as a simple asphyxiant gas. 

Toxicology. Methane acts as a simple asphyxiant by causing oxygen deprivation at very high concentrations. 

Osbern LN Simple asphyxiants. Environmental and Occupational Medicine, pp 285-288,1983... 

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