Excavation
and trenching are among the most hazardous construction operations, but
taking some basic precautions can prevent accidents and save lives.
A 27-year-old
construction worker was digging a trench for a new sewer line when the
walls of the 10-foot-deep excavation collapsed around him, burying him
under mounds of clay and dirt. Only his hand extended above the dirt,
signaling his coworkers where he was as they rushed to the scene to dig
him out using their hands and hand shovels. Forty-five minutes later,
a cut and bruised but fully conscious worker stepped from the hole, surviving
Many workers
aren’t so lucky. Excavation and trenching are among the most hazardous
construction operations, and the weight of soil sloughing off the side
of an unprotected trench can cause a crushing blow to an employee at the
bottom, resulting in a serious injury or fatality. During 2000 alone,
38 construction workers died in excavation and trench cave-ins, according
to the Bureau of Labor Statistics’ “Census of Fatal Occupational
Injuries.” Last fall, for example, a 31-year-old Illinois man died
after a piece of a trench wall broke loose and fell on him while he was
working in a five-foot-deep trench. In Arizona, a 33-year-old man stepped
out of a stacked trench box system when the trench collapsed, suffocating
him. In Missouri, a worker was laying pipe in a 12-foot-deep trench with
no shoring when the trench wall collapsed, burying him. Four hours later,
rescuers finally were able to recover his body.
OSHA's excavation standard requires employers to provide sloping, benching, shoring, or shielding to protect workers in excavations five feet or deeper
According to Jim
Boom, an occupational safety and health specialist in OSHA’s Directorate
of Construction, most of these fatalities would have never have occurred
if the people responsible for providing a safe workplace had complied
with well-known safety requirements for trenches and excavations. OSHA’s
excavation standard requires employers to provide sloping, benching, shoring,
or shielding to protect employees in excavations five feet or deeper.
The only exception is for a trench dug in stable rock where there is no
loose soil or likelihood of a cave-in.
Which system to use
is up to the contractor and depends on a variety of factors such as the
type of soil, water content, depth and angle of the cut, changes in weather
such as a freeze and thaw, and other activities in the vicinity that might
vibrate the trench walls or cause equipment or materials to roll into
the trench. Regardless of the system a contractor selects, Boom said,
it must meet the requirements of the OSHA standard.
After putting a protective
system into place, contractors must designate a “competent person”—someone
trained to recognize hazards and authorized to take prompt action to correct
them—to inspect the site daily or more often if conditions change.
They also must take specific steps to protect workers involved in excavation
work who are exposed to falls, falling loads, and mobile equipment.
For those who do not
follow these required steps, the costs can be high. “Contractors who
take risks to save time at the expense of protecting employees should consider
the potential consequences,” said Boom. “The ultimate consequences
are the loss of lives or disabling injuries. Taking shortcuts could also
lead to damaged equipment, property or structural damage, loss of insurance
or increased premiums, lawsuits, public scrutiny from bad press, and any
penalties that may result from an OSHA inspection.” Boom says these
costs can be devastating to a company or corporation.
In October, OSHA
proposed $248,000 in fines against a Franklin, Mass., construction contractor
for willful and repeated failure to protect its workers against potentially
deadly cave-ins. “Excavation collapses are sudden, swift, and often
deadly,” said Brenda Gordon, OSHA Area Director for South Boston.
“There’s no excuse for an employer time and time again failing
to supply such a vital, common-sense—and legally required—safeguard.”
Also in October,
OSHA proposed $56,000 in penalties against a Frisco, Texas, excavation
company that failed to protect its employees from a possible cave-in while
installing a water main at the of a trench. The previous month, two Ludlow,
Mass., contractors were fined $110,000 for the repeated failure to protect
employees against cave-in hazards, and a contractor in Rehoboth Beach,
Del., received $49,500 in penalties following an April 5 accident in which
a 22-year-old pipe layer died while installing storm drain piping in an
unprotected trench that caved in.
Earlier
this year, an Alabama waterproofing contractor failed to shore or slope
trench walls or otherwise protect workers in a nine-foot-deep excavation.
When the unprotected trench collapsed, two workers escaped, but one was
buried and suffocated before he could be rescued. OSHA issued $99,000
in fines, including one willful and five serious violations. In Dallas,
OSHA cited an engineering firm for violations that caused a cave-in that
buried a 41-year-old engineer in a trench about 15 feet deep. The contractor
was charged with providing no cave-in protection, insufficient training,
and no onsite worker supervision.
The newly revised
OSHA Publication 2226, “Excavations,” provides more information
about excavations and trenches. It is available on the OSHA website at
www.osha.gov. Click
on Publications under Newsroom. JSHQ
A contractor reads a penetrometer to determine the best protective system to use in an excavation to prevent a cave-in
Trenching Tips
Exercise leadership
and commitment to a good safety and health program.
Train workers
to follow safe work practices and recognize hazardous conditions.
Choose the most
appropriate protective system for the job and apply it according to
OSHA requirements.
Provide support
systems such as shoring, bracing, or underpinning to keep nearby structures
stable.
Designate a “competent
person” who can identify hazards and has the authority to take
prompt action to correct them.
Inspect the site
daily for possible cave-ins, failures of protective systems and equipment,
hazardous atmospheres, or other hazardous conditions.
Discourage surface
crossing of trenches.
Provide a convenient,
easy-to-use means of access to and exit from the trench.
Protect workers
from loads or objects falling from lifting or digging equipment.
Prevent water
accumulation whenever possible.
Test excavations
for oxygen deficiency or hazardous atmospheres and require protective
equipment when needed.
Use warning systems
for mobile equipment operating at the site.
Occupational Safety
& Health Administration
200 Constitution Avenue, NW
Washington, DC 20210 www.osha.gov
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