Hazards of Chemicals and Gases
Basic Safety Precautions Regarding Compressed Gases
Compressed and liquified gases are widely useful due to properties including high heat output
in combustion for some gases, high reactivity in chemical processing with other gases, extremely
low temperatures available from some gases, and the economy of handling them all in compact
form at high pressure or low temperature. These same properties, however, also represent
hazards if the gases are not handled with full knowledge and care.
Practically all gases can act as simple asphyxiants by displacing the oxygen in air. The chief
precaution taken against this potential hazard is adequate ventilation of all enclosed areas in
which unsafe concentrations may build up. A second precaution is to avoid entering unventilated
areas that might contain high concentrations of gas without first putting on breathing apparatus
with a self-contained or hose-line air supply. A number of gases have characteristic odors which
can warn of their presence in air. Others, however, like the atmospheric gases, have no odor or
color. Warning labels are required for compressed and liquified gas shipping containers. Similar
warning signs are placed at the approaches to areas in which the gases are regularly stored and
Some gases can also have a toxic effect on the human system, either inhalation, through high
vapor concentrations, or by liquified gas coming in contact with the skin or the eyes. Adequate
ventilation of enclosed areas serves as the chief precaution against high concentrations of gas.
In addition, for unusually toxic gases, automatic devices can be purchased or built to monitor
the gas concentration constantly and set off alarms if the concentration approaches a danger
point. Precautions against skin or eye contact with liquified gases that are toxic or very cold,
or both, include thorough knowledge and training for all personnel handling such gases, the
development of proper procedures and equipment for handling them, and special protective
clothing and equipment (for example, protective garments, gloves, and face shields).
With flammable gases, it is necessary to guard against the possibility of fire or explosion.
Ventilation, in addition to safe procedures and equipment to detect possible leaks, represents a
primary precaution against these hazards. If fire breaks out, suitable fire extinguishing apparatus
and preparation will limit damage. Care must also taken to keep any flammable gas from
reaching any source of ignition or heat (such as sparking electrical equipment, sparks struck by
ordinary tools, boiler rooms, or open flames).
Oxygen poses a combustible hazard of a special kind. Although oxygen does not ignite, it
lowers the ignition point of flammable substances and greatly accelerates combustion. It should
not be allowed closer than 10 feet to any flammable substance, including grease and oil, and
should be stored no closer than 10 feet to cylinders or tanks containing flammable gases.