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Carbon Dioxide Safety Information

Carbon dioxide is a compound of carbon and oxygen in proportions by weight of about 27% carbon to 73% oxygen. It is a gas at normal atmospheric temperatures and pressures. Carbon dioxide is colorless, odorless, and about 1.5 times as heavy as air. It is a slightly acid gas which is felt by some persons to have a slight pungent odor and biting taste.

Carbon dioxide is relatively non-reactive and nontoxic. It will not burn, and it will not support combustion or life. When dissolved in water, carbonic acid is formed. Solid carbon dioxide (“dry ice”) is used quite extensively to refrigerate dairy products, meat products, frozen foods, and other perishable foods while in transit. Gaseous carbon dioxide is used to carbonate soft drinks, for pH control in water treatment, in chemical processing, as a food preservative, metal welding and as a growth stimulant for plant life. Liquid carbon dioxide is used as an expendable refrigerant for freezing and chilling food products, for stimulation of oil and gas wells, etc.

Acute and chronic health effects

Carbon dioxide is normally present in the atmosphere at about 0.035% by volume. It is also a normal end product of human and animal metabolism. The exhaled breath contains up to 5.6% carbon dioxide. The greatest physiological effect of carbon dioxide is to stimulate the respiratory center, thereby controlling the volume and rate of respiration.  It is able to cause dilation and constriction of the blood vessels and helps to control the pH of the blood. Carbon dioxide acts as a stimulant and a depressant on the central nervous system.

Increases in heart rate and blood pressure have been noted at a carbon dioxide concentration of 7%. Prolonged exposure at this concentration may cause labored breathing, headache, dizziness, and sweating. Concentrations of 10% and above will cause unconsciousness in one minute or less. Impairment in coordination has been noted during prolonged exposure to concentrations of 3% carbon dioxide even while the oxygen concentration was 21 percent. 

Inhalation of gaseous carbon dioxide can adversely affect body function. Gaseous carbon dioxide is an asphyxiant. Concentrations of 10% or more can produce unconsciousness or death. Lower concentrations may cause headache, sweating, rapid breathing, increased heartbeat, shortness of breath, dizziness, mental depression, visual disturbances, and shaking. The seriousness of these symptoms is dependent on concentration and length of time the individual is exposed. Carbon dioxide when inhaled in elevated concentrations may act to produce mild narcotic effects, stimulation of the respiratory center, and asphyxiation depending on the concentration present and the duration of exposure. Chronic effects of CO2 have received little attention and there is very little information available on long term health effects from chronic exposure. Skin, eye, or mouth contact with dry ice or compressed carbon dioxide can cause tissue damage or burns.

The acute effects of carbon dioxide and causal concentrations are listed below:

Permissible exposure limit: The OSHA PEL-TWA for carbon dioxide is 5,000.

Warning properties: Carbon dioxide is an odorless gas. Since carbon dioxide has no odor, and since no quantitative information is available relating its irritant effects of to air concentrations, this product has been treated as a material with poor warning properties.

Respirators: Personnel, including rescue workers should not enter areas in which the carbon dioxide content exceeds 3% by measurement unless wearing self-contained breathing apparatus or air-line respirators.

First aid care

First aid for inhalation:

• if a person has inhaled large amounts of carbon dioxide and is exhibiting adverse effects, move the exposed individual to fresh air at once
• if breathing has stopped, perform artificial respiration
• keep the person warm and at rest
• seek medical attention at once
• fresh air and assisted breathing are appropriate for all cases of overexposure to gaseous carbon dioxide

First aid for skin contact:

• if solid carbon dioxide (dry ice) or compressed CO2 gas comes in contact with the body, stop the exposure at once
• if frostbite has occurred, seek medical attention

First aid for eye contact:

• if the eyes are involved, obtain prompt medical attention

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