DOE/EH-0110 --- Issue No. 89-03 --- 10/89
Employee Suffers Oxygen Deprivation
When Air Line is Accidentally Hooked
into
Nitrogen Drop Instead of Plant Air Supply
An employee at a DOE facility had a narrow escape a few weeks ago when he
accidentally hooked his air manifold and air purifying accessory (APACC) unit
into a nitrogen drop and was deprived of oxygen long enough to black out. As
the worker was going into the fluorine generating room to change instrument
lines on the pressure indicators, he hooked his APACC unit into what he
thought was the plant air supply. Instead, he'd accidentally hooked into a
nitrogen header drop. While he was suiting up to go into the room, he
blacked-out, fell, and hit his head. The person who was acting as the
emergency backup called the emergency squad, and the employee was transported
to the plant medical facility. A couple of hours later he was transported to
the local hospital for observation. Luckily, the worker suffered only from
nausea and a headache following the accident: the consequences could have been
much more serious.
Mix-up Could Have Been Avoided by Dissimilar Couplings, Color-Coded Piping,
and a Different Source of Supplied Air
Investigation into the accident indicated that three factors had contributed
to the mix-up that caused this accident: (1) couplings on the nitrogen lines
were identical to those for the plant air system, (2) the nitrogen lines were
not properly color-coded, and (3) the plant air system was used to supply
respirable air.
Couplings -- Because identical couplings were used on both the plant air
supply and the nitrogen supply, the employee had no difficulty hooking up to
the wrong supply system.
In this particular area of the facility, the nitrogen drop and the plant
air drop are side by side, and both the air supply and the nitrogen hookup
system have the same type of couplings. Since the couplings are identical
for both supplies, the worker was able to hook up his APACC to the wrong
supply quite easily, with no reason to suspect he was making an error.
After the accident it was recommended that the couplings on the nitrogen
system throughout the facility be replaced with another type of coupling;
thus making it impossible for workers to connect to the wrong line.
Color Coding -- All of the piping in the accident area had recently been
spray-painted white.
Nitrogen lines are generally indicated with blue paint throughout the plant
to clearly differentiate them from the plant's air supply lines. However,
since blue paint had not yet been applied to the piping, the worker was
unable to take advantage of this visual cue when he connected up his APACC.
Following the accident, all nitrogen-drop piping was identified and
properly painted.
Air Supply -- The mix-up might not have occurred had an air supply other than
the plant air drop been used.
The plant air supply is hard-piped into all areas of the facility for use
as required. However, the risk of a mix-up was inherent in the use of a
plant air supply for respirable air, given the configuration at the
facility. The plant air supply is no longer used at this facility without
prior approval from the Industrial Hygiene department.
Meeting DOE Requirements Will Prevent Similar Accidents
Implementing color coding and labeling for all gas liquid supply lines is a
good safety practice that should be followed to ensure that mix-ups like the
one described above do not occur. However, Code of Federal Regulations (CFR)
and DOE requirements regarding dedicated air line couplings and the training
of personnel who use supplied-air respiratory protection systems must be met
at all DOE facilities. DOE Order 5483.1A and 29 CFR 1910.134 specifically
detail these requirements, which are briefly outlined below.
- Minimal Acceptable Requirements -- The following are among the minimal
requirements for an acceptable program:
- Written standard operating procedures governing the
selection and use of respirators.
- User training and instruction in the proper use of
respirators and their limitations.
Specific requirements related to couplings and employee training include the
following:
Although the plant air supply may not always be an optimal choice to provide
respirable air, its use is not prohibited. However, when choosing a source of
respirable air, DOE Order 5483.1A and 29 CFR 1910.134 should be followed. With
regard to air quality, Item 11(d) of these requirements states that:
- Oxygen must never be used with air line respirators.
- Breathing air may be supplied to respirators from cylinders or air
compressors.
Recommendations
To help ensure that workers do not inadvertently hook up to inert gas supplies
rather than to respirable air, the following recommendations should be
implemented at DOE facilities.
- Ensure that all requirements related to respiratory protection (as
outlined in DOE Order 5483.1A and 29 CFR 1910.134) are met.
- Determine if similar couplings are used for both the plant air supply
system and other inert gas delivery systems. Replace couplings on inert
gas systems with another, unique type of coupling.
- Develop a maintenance procedure to address supply-line
identification/painting. Stress the purpose of color-coding and the
importance of completing detail painting in a timely fashion to ensure
that this visual cue is always available to aid workers.
- Eliminate the use of a plant air system for respirable air, if
possible. If the plant air supply is used, work should be carefully
supervised.
This publication is one of several series of bulletins published so that DOE
program managers and contractors can share information about potential
occupational safety problems relevant to DOE operations. For more information
or additional copies, contact the Performance Evaluation Division, Office of
Safety Compliance, Assistant Secretary for Environment, Safety & Health, U.S.
Department of Energy, Washington, DC 20545; telephone (301)903-3294.