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Asphyxia

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Asphyxiation

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Asphyxiant

Definition

• An asphyxiant is a substance that can cause unconsciousness or death by suffocation (asphyxiation). Asphyxiants which have no other health effects and are sometimes referred to as simple asphyxiants.

  Asphyxiation is an extreme hazard when working in enclosed spaces. Be sure you are trained in confined space entry before working in sewers, storage tanks etc. where gases such as methane may displace oxygen from the atmosphere.

Additional Info

Asphyxiants work by displacing so much oxygen from the ambient atmosphere that the hemoglobin in the blood can not pick up enough oxygen from the lungs to fully oxygenate the tissues. As a result, the victim slowly suffocates.

The normal composition of air is:

Name	Formula	% by volume
Nitrogen	N2	78.03
Oxygen	O2	20.99
Argon	Ar	0.94
Carbon dioxide	CO2	0.033
Neon	Ne	0.0015

According to the Canadian Centre for Occupational Health and Safety (CCOHS) the health effects of asphyxiation are:

% O2 by volume	Symptoms or effects
16 to 12	Breathing and pulse rate increased, muscular coordination slightly disturbed
14 to 10	Emotional upset, abnormal fatigue, disturbed respiration
10 to 6	Nausea and vomiting, collapse or loss of consciousness
Below 6	Convulsive movements, possible respiratory collapse and death

Examples of asphyxiating gases are nitrogen (N₂), helium (He), neon (Ne), argon (Ar), methane (CH₄), propane (CH₃CH₂CH₃), and carbon dioxide (CO₂).

MSDS Relevance

All of the asphyxiants listed above are odorless and tasteless except carbon dioxide. You can become unconscious by inhalation of these gases without realizing they are present. Again, follow OSHA-approved protocols for confined space entry into sewers, storage tanks etc. Also note that some of these materials (methane and propane, for example) are also flammable and can form a flammable mixture in air. Remember also that simple air-purifying respirators or dust masks do not protect you from asphyxiation in an oxygen-deficient atmosphere. See the first link below for accidents involving supplied air respirators! The abbreviations S/A or SA are sometimes used for "simple asphyxiant" in describing lethal or regulatory compliance concentrations.

Get your confined space entry training videos and pamphlets at Safety Emporium.

Further Reading

• OSHA has a publication titled Deaths Involving the Inadvertent Connection of Air-line Respirators to Inert Gas Supplies
• OSHA Fatal Fact Sheet #36 discusses a sandblaster who was asphyxiated when his air supply was hooked up to a nitrogen line instead.
• OSHA Fatal Fact Sheet #39 discusses an asphxiation death during confined space entry into a manhole.

See also: anoxia, asphyxia, asphyxiation.

Additional definitions from Google and OneLook.

Disclaimer: The information contained herein is believed to be true and accurate, however ILPI makes no guarantees concerning the veracity of any statement. Use of any information on this page is at the reader's own risk. ILPI strongly encourages the reader to consult the appropriate local, state and federal agencies concerning the matters discussed herein.