OSHNC Hazard Advisory #1
Hazard Review Involving Confined Spaces, Trenching, and Related Safety Standards by NCDOL
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/VX. Department of Labor
Clear and Present Dangers
The newspaper headline read, “Two Sewer Workers
Killed in Iowa.” Unfortunately serious workplace
injuries and deaths transcend state lines and other
territorial boundaries. Fortunately hazard awareness
and workplace safety can, too. Hazards associated
with confined spaces and trenching should always be
considered and treated as clear and present dangers.
To view them otherwise could result in another tragic
event.
In recent years, the Division of Occupational Safety
and Health in the North Carolina Department of
Labor (OSHNC) has issued several advisories
pertaining to confined spaces and trench work. Such
hazardous conditions may include, but arc not limited
to, possible cave-ins, failure of protective systems,
hazardous atmospheres, water accumulation, access
to and egress from confined spaces, and excavation
and trench -related work. No state is immune to tragic
events involving these activities, as the following
details document:
Two construction workers in the process of re-lining
city sewer pipes with a plastic resin died in Iowa on
July 8, 2002. They were employed on the sewer
project by a sub -contractor for the city of Dcs
Moines. Regrettably nine others were also injured as
a result of this accident. The Bureau of National
Affairs (BNA), recognized news media source for
occupational safety and health, received an account
of the incident from a Dcs Moines Fire Department
spokesperson. Specifically, the deceased workers
collapsed in a 16-foot trench and were recovered
from a pool of water at the bottom of the pit.
According to Jim Mason, acting assistant chief of
operations, the remaining workers were injured when
they tried to rescue the first victims. All five
remained hospitalized on July 9, one of them in
critical condition. Mr. Mason stated that four
firefighters were also injured in the rescue. Both the
injured workers and firefighters experienced
symptoms that were consistent with hydrogen sulfide
exposure, including convulsions. The medical
examiner concluded that the two workers died from
drowning after falling unconscious. They had been
working in an area of the sewer line that contained
stagnant water. Disturbing the water resulted in the
emission of hydrogen sulfide gas. (Hydrogen sulfide
is a natural byproduct produced by the decomposition
of organic materials such as sewage.) Since hydrogen
sulfide gas is heavier than air, it can displace oxygen
in the air, and probably caused these workers to lose
consciousness because of a lack of oxygen. It is
unlikely that the gas itself incapacitated them.
However, in their effort to rescue their two downed
co-workers, five additional workers, and
subsequently four fire fighters, were affected by the
toxic gases.
Hazard awareness and assessment as well as
knowledge of safety requirements arc paramount for
work activities that involve excavation, trenching and
confined spaces. Such knowledge is also essential to
successful rescue or emergency operations associated
with accidents and injuries in these areas. Sharing
information is one way to address this tragic event
and hopefully prevent others throughout North
Carolina and elsewhere.
Relevant OSHA Standards
1910.146 — Permit Required Confined Spaces
1926.651-- Specific Excavation Requirements
A more complete listing of standards referenced, as
well as others, can be viewed at these websites:
http://osha. gOV, see Regulations (Standards - 29
CFR); http://www.nclabor.COin, Publications,
Industry Guide Series (e.g. IG #01 and IG #14)
Definitions:
''Competent person" means one who is capable of
identify ing existing and predictable hazards in the
surroundings, or working conditions which are
unsanitary, hazardous, or dangerous to employees,
and who has authorization to take prompt corrective
measures to eliminate them.
" Hazardous atmosphere" is an atmosphere that by
reason of being explosive, flammable, poisonous,
corrosive, oxidizing, irritating, oxygen-deficient,
toxic or otherwise harmful may cause death, illness
or injury to persons exposed to it
"Non-permit confined space" means a confined
space that does not contain or, with respect to
