OH-94-1 Supplied Breathing Air Systems Are Inadequately Maintained
OFFICE OF HEALTH
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HEALTH HAZARD ALERT
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Assistant Secretary for Environment, Safety and Health
U. S. Department of Energy Washington, D.C.
Issue 94-1 February 1994
Supplied Breathing Air Systems Are Inadequately Maintained
Several workers have died as a result of using supplied breathing
air systems (SBAS) that are not maintained adequately or designed
properly.
The National Institute for Occupational Safety and Health (NIOSH)
recently reviewed 11 related deaths that occurred nationwide from
1984 to 1988. These deaths were caused by the accidental
connection of SBAS respirator air lines to inert gas supplies
rather than to breathable air. When a respirator air line is
connected to a gas source instead of a breathable air source, the
user of the SBAS has little to no warning before losing
consciousness, and possibly dying from suffocation.
All supplied breathing air respirators, whether set up for use
with a suit, hood, or face piece must have a line (hose) with
couplings (attachments) that are incompatible with couplings for
unbreathable gas systems. NIOSH concluded that incompatible
couplings would have prevented workers from connecting their air
hoses to an unbreathable gas and dying. Four of the eleven
deaths were caused when lines that normally carried breathable
air were used for another purpose and not cleansed of
unbreathable gas. Department of Energy (DOE) management and
operating (M&O) facilities should institute a strict policy to
prevent the use of any component of a supplied breathing air
system for any other purpose.
DOE Order 5480.4 requires that DOE M&O facilities use couplings
that are exclusive for breathing air, as mandated by Occupational
Safety and Health Administration (OSHA) regulations and the
American National Standards Institute (ANSI) Z88.2 Standard.
In 1990, OSHA investigated the death of a worker who suffocated
as a result of breathing air from a cylinder marked "breathing
air" that had not been properly reconstituted (air that is
restored to a breathable condition from pure nitrogen and
oxygen). The cylinder contained less than 1 percent oxygen. The
new ANSI Standard Z88.2-1992 now requires that users and fillers
of SBAS cylinders that contain reconstituted air or breathing
air, test these cylinders for the proper oxygen concentration.
ANSI Standard Z88.2-1992 requires that a supplied air respirator
uses Type 1 Grade D breathable air, as defined in ANSI/Compressed
Gases Association Specification G7.1-1989.
SBAS's equipment such as couplings, piping, reservoirs,
cylinders, and compressors should only be used for breathing air.
DOE facility supervisors must enforce:
o the incompatibility between supplied air respirator
couplings and other gas couplings;
o testing of all breathing air cylinders, particularly
those received from suppliers, for the proper oxygen
concentration; and
o assurance that all breathing air systems comply with
applicable standards.
For more information, contact Carlos Coffman, Industrial Hygiene
Programs Division, EH-412, at (301) 903-6493.