EH-9308 Issue No. 8, August 1993 Occupational Safety Observer
AUGUST 1993
Occupational Safety Observer
Crane Safety
Balancing the Load
To a crane operator, few experiences can be as frightening as when a
crane becomes unbalanced while a load is being lifted or when the crane
collapses under the weight of an excessive load. In April 1993, cranes
became unbalanced during two separate incidents at DOE sites. This
article discusses these incidents, as well as a related industrial
incident in which a crane collapsed.
The DOE incidents
The first of the two incidents at DOE sites occurred on April 28,
1993, when a crane at the Hanford Site became unbalanced while the boom
was being lowered. The operator was preparing to lift a waste cask and
made the mistake of lowering the boom too far, thereby shifting the
crane's center of gravity. As the crane's rear outriggers lifted off the
ground, the operator quickly raised the boom and restored the crane's
balance. No damage occurred, and no one was injured.
The primary cause of the incident was attributed to the operator's
lack of familiarity with the crane. This particular crane had five
outriggers rather than four, a more common configuration. The operator
was unaware of the fifth outrigger and had not extended it to stabilize
the crane. Using the fifth outrigger could have prevented the incident.
The second DOE incident occurred 2 days later, on April 30, 1993. A
worker at the Bryan Mound site used an 18-ton mobile crane to off-load an
8,300-pound electric motor. The worker lifted the motor and then rotated
the boom to position and lower the motor. The weight of the load caused
the crane to tip forward. The worker quickly lowered the load, preventing
any damage to the crane. However, the electric motor being lifted and two
others located on the ground were damaged.
Although the worker in this instance was a certified crane operator,
his lack of experience contributed to the incident. He underestimated the
weight of the lift by 2,000 pounds. After lifting and rotating the load
successfully, he attempted to lower the boom in order to extend the reach
of the crane to the drop zone, at which point the crane became unstable.
The industrial incident
Failure to determine the correct weight of a load had more serious
consequences in an industrial accident that occurred in Dayton, Ohio, on
March 28, 1991. In this incident, a crane collapsed while removing an
air-conditioning unit from the roof of a building. The crane operator had
been told that the unit weighed 3,400 pounds; it actually weighed 5,510
pounds. The crane had a rated capacity of only 4,800 pounds.
OSHA has cited the operator of the crane for failing to take
reasonable steps to verify the weight of the load, a violation of 29 CFR
1926.500(a)(1). Because the crane operator was a subcontractor to the
rigging company hired to remove the air-conditioning unit, subcontractor
management argued that the rigger was responsible for determining the
unit's weight.
This argument did not sway the Secretary of Labor, who maintained
that the crane operator should have taken reasonable steps to verify the
information provided by the rigging company. According to the brief filed
recently in the Sixth Circuit of the U.S. Court of Appeals, no one from
the subcontractor organization examined the unit before the lifting
operation began. The unit's size should have led workers to question the
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weight estimate. The crane operator had a second opportunity to question
the 3,400-pound estimate when it was learned that the replacement unit
weighed 5,000 pounds. Finally, even if the 3,400-pound estimate had been
correct, the additional weight of crane attachments meant that
the total load weight would have come within 100 pounds of the crane's
rated capacity.
Lessons learned
These incidents suggest several general guidelines for the safe use
of cranes:
o Crane operators must know the weight of a load. If a crane
operator is unsure about the weight of a load, he or she should
refer to the shipping ticket or other documentation. Crane
operators should also ensure that all calculations regarding
lifts are correct; for example, the hook distance should
be measured from the crane's centerline of rotation, not from
the base of the boom.
o Crane operators must be trained and qualified to operate their
equipment. Completion of a training course does not ensure that
a worker is qualified; on-the-job training is an important
supplement to formal instruction. Training isn't complete until
proficiency can be consistently demonstrated.
o Qualified personnel should supervise crane operations.
Appropriate supervision is another important supplement to
formal instruction. The inexperienced crane operator at Bryan
Mound was not supervised during the lift.
o Crane operators must be familiar with their equipment. The
operator associated with the Hanford incident was a certified
crane operator, but he was unfamiliar with the particular crane
being used and did not know about the fifth outrigger. An
operator should be qualified on the specific piece of equipment
he or she will operate, as well as being qualified on an
equipment class (such as cranes). Equipment placards can be
helpful for identifying unusual equipment characteristics.
References
First incident: ORPS # RL--WHC-SOLIDWASTE-1993-0016
Second incident: ORPS # HQ--SPR-BM-1993-0007
Two Deaths
Rescue Attempt Ends Tragically
A recent accident in a shallow well serves as a reminder about the
hazards of confined-space rescue -- for both victim and rescuer. In this
unfortunate accident, an untrained worker using inadequate equipment
attempted to rescue a coworker from a shallow well. When this impulsive
rescue attempt failed, both men became trapped and died.
The accident
On May 1, 1993, the two employees of an independent contractor were
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cleaning a shallow residential well in La Plata, Maryland. One worker
used a sawhorse equipped with a winch, a cable, and a bucket-like device
to lower his partner into the well. When the worker inside the well
reported that he felt lightheaded, his partner made several attempts to
bring him back to the surface. After these attempts failed, the worker on
the surface had himself lowered into the well by bystanders. When these
bystanders tried to raise both men from the well, the combined weight of
the two men, estimated at 450 pounds, caused the seat to break away from
the cable. Neither of the workers had supplemental oxygen devices, and
fans were not available to force air into the well.
Members of the La Plata Volunteer Fire Department arrived within
minutes after bystanders called 911. The second worker to enter the well
was able to talk to the firefighters but soon fell silent. Concluding
that the second worker had slipped beneath the water, the firefighters
decided to enter the well to effect a rescue, even though air masks had
not yet arrived at the scene. According to John Latimer, Deputy Chief of
the La Plata Fire Department, "The guy went underwater and we went in."
Firefighters were able to retrieve one of the two workers, but efforts to
revive him failed.
Three volunteers from the Charles County (MD) dive rescue team
arrived and entered the well to retrieve the other worker, who was still
underwater. However, air masks used by the divers did not meet the
requirements established by the Maryland Occupational Safety
and Health Administration for such a rescue. Because it was difficult to
maneuver in the confined space of the well, divers were forced to enter
one at a time and were unable to remove the remaining worker. These
divers were later treated at a local hospital for oxygen deprivation.
Rescuers from the Prince Georges County (MD) Bureau of Special Tactical
Operations were then summoned to assist with the rescue. These rescuers
had specialized training in confined-space rescue and were equipped with
full-body harnesses and helmets, including a direct air supply. This
equipment allowed greater mobility than did the traditional diving gear
used by the dive rescue team. A rescuer from this team put a harness
around the remaining worker, who was pulled out and pronounced dead at the
scene. Nearly 5 hours after the incident began, it was over.
Lessons learned
According to Craig Black of the Prince Georges County Fire
department, "over 50 percent of the fatalities in confined spaces
are . . . would-be rescuers. Someone goes in and doesn't recognize the
hazards and gets overcome." When things went wrong, the worker on the
surface went to the aid of his trapped partner. This would-be rescuer
certainly had the best of intentions; however, he lacked the training and
equipment necessary to rescue his partner -- or to save his own life. If
these workers had prepared a viable contingency plan for dealing with such
an accident, the incident might have ended differently.
The decision to send a firefighter into the well without an air mask
to effect a rescue was also risky -- although it is certainly easy to
understand why dedicated professionals would have difficulty standing by
when a man's life was in danger. The duty of a first responder is to
evaluate the situation objectively -- not to risk compounding the problem.
Afterward, John Latimer said, "We didn't have the equipment we should
have. We should have backed off and waited. I put some people in
jeopardy. Next time I'll know better."
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OSHA regulations
OSHA regulation 29 CFR 1910.146 addresses training for confined-space
rescue as follows:
o Each member of the rescue team should be provided with, and
trained in the use of, personal protective and rescue equipment.
o Each member of the rescue service is required to practice making
confined-space rescues at least once every 12 months. The
rescue unit from the Prince Georges Bureau of Special Tactical
Operations had such training.
o Proper retrieval equipment for confined-space rescue must be
used.
The lifting equipment used by the independent contractors was crude.
"Every time these men went down a well using the equipment they had, their
lives were at risk," said Tom Johnston, Director of Emergency Management
for Charles County.
OSHA requires that retrieval systems must have a chest or full-body
harness with a retrieval line attached at the center of the entrant's back
near shoulder level or above the entrant's head. (Wristlets may be used
if they are judged to be safer and more effective.) The retrieval line
should be attached to a mechanical device or fixed point outside the
confined space so that emergency operations can begin as soon as the
rescuer becomes aware that rescue is necessary. The rescue unit that
eventually retrieved the initial victim used this type of equipment.
Effective Prevention
A few basic steps can be taken to prevent this type of accident:
Workers
o Workers should prepare a contingency plan in the event of an
accident. The plan should include provisions for appropriate
equipment and backup assistance.
o Workers trained in the use of proper techniques should test the
atmosphere of a confined space before they begin work, and the
space should be ventilated to remove the hazardous atmosphere.
o Workers should be provided with, and trained in the use of,
equipment necessary to perform the job safely, including
personal protective equipment.
Rescuers
o The rescue plan should be developed and rescuers should be
briefed before the job begins.
o Rescue teams should be trained to respond effectively in the
event of an emergency.
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Following these steps will not only contribute to more effective
rescue efforts, but will better protect the safety of the rescuers.
Good Practice
Creating Better Spill Barriers
Engineers from the Bechtel Corporation and the Naval Petroleum
Reserve (NPR) in Tupman, California, have found an economical and
effective solution for containing hazardous material spills. Engineers at
NPR installed corrugated-aluminum pipes filled with cement around storage
tanks. These pipes replaced dirt berms, which have traditionally been
used as spill barriers. In the long term, corrugated-pipe barriers are
easier to maintain and may be more effective than dirt berms.
Dirt berms have always been susceptible to damaging environmental
influences and must be reconstructed about every 2 years. This 2-year
maintenance cycle can make dirt berms an expensive choice for spill
barriers around permanent structures.
Corrugated-aluminum pipes offer several specific advantages when used
as spill barriers. Corrugated aluminum is a light, rigid material that
can withstand impact and vibration caused by heavy equipment. It can also
withstand the damaging effects of water, burrowing rodents, and other
erosive influences. In addition, pipes passing through corrugated
aluminum can be adequately sealed to the aluminum, increasing the
integrity of the spill barrier. Dirt berms have an important place in a
variety of applications. However, the advantages of corrugated-aluminum
pipes represent a valuable technological advance.
According to Fred Shokooh, a Bechtel engineer at NPR, the use of
corrugated-aluminum pipes will eventually become more widespread at
permanent industrial installations.
Inadvertent Activation
Sprinkler System Inundates Motorists
In two separate incidents, motorists on Interstate 5 in Seattle,
Washington, were fortunate to escape serious injury when a sprinkler
system in a tunnel activated without warning. The two activations
occurred within less than a week. The cause of the first activation was
attributed to a system malfunction, but the second activation was probably
caused by workers attempting to diagnose the first activation.
The incidents
Because Interstate 5 passes under the Washington State Trade and
Convention Center in downtown Seattle, an overhead sprinkler system was
installed in the tunnel to protect the center from the effects of fire.
At 11:00 p.m. on June 6, 1993, the sprinkler system activated without
warning, spraying fire-suppressing foam and water on the northbound lanes
of Interstate 5 for almost 30 minutes. The deluge caused two accidents,
one involving three cars and another involving a motorcycle. No one was
seriously injured. A Washington State Department of Transportation worker
had to be summoned from home to turn off the sprinklers.
Two days later, at 11:15 a.m. on June 8, 1993, workers were
attempting to troubleshoot the sprinkler system. The workers believed
that the sprinklers could not activate because the pumps feeding the
system had been shut down and the valves necessary to isolate the system
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had been closed. The sprinklers did go off, however, when a trained
technician attempted to locate the fault in the system. A five-car pileup
resulted. According to one motorist involved in the accident, "It was the
same feeling as being in a car wash. You just can't see anything." Once
again, no one was seriously injured. Midday traffic was heavy, and the
incident caused freeway traffic to back up for several miles.
The sprinkler system has been locked out to prevent further
activations. Transportation officials have asked for assistance from the
company that designed the system. Officials also promised that future
troubleshooting activities will be conducted at night. Until
the sprinklers are repaired, flammable loads can't be transported through
the tunnel.
Officials remain uncertain about why the sprinklers activated. A
Department of Transportation spokesman suggests that a computer glitch may
have been responsible. The investigation is still under way.
Lessons learned
Even though the causes of these activations are not known, the second
occurrence reiterates an obvious lesson -- workers must ensure that
systems are effectively locked out before troubleshooting activities
begin. A lockout should be verified to ensure that the energy source has
in fact been isolated. This is important not only for the safety of those
working on the system, but for that of anyone who might be affected by
inadvertent operation of the system.
In some instances, a system that has been locked out can't be
thoroughly tested because the lockout has deactivated the system. If a
system can't be locked out for this reason, or if the effectiveness of the
lockout is in question, workers should eliminate any hazards that could
result from inadvertent activation during testing. In the future, for
example, Department of Transportation workers plan to reroute traffic
during testing.
The first activation suggests another lesson: Workers should have
the training to deal with any emergency that may occur during their shift.
When the sprinklers activated the first time, no one on duty knew how to
turn them off and there was a substantial delay while a knowledgeable
off-duty worker was summoned to the scene. If necessary, supplemental
training should be provided on emergency systems.
Both lessons point to deficiencies related to training. Workers were
not sufficiently familiar with the sprinkler system to deactivate it
(although the lockout failure may have been caused by a system
malfunction). As with most emergency systems, the sprinkler system is
seldom used -- it is designed to activate only when a serious accident
occurs in the tunnel. As a result, workers are not likely to become
familiar with the system unless specific, refresher training is conducted.
Overview of Site Safety
Review of Type A and B Accident Investigations
Type A and B investigations are required for the most serious
accidents at DOE sites. This article briefly summarizes the results of 34
investigations that have occurred since mid-1990.
Types of accidents
DOE requires a Type A or B investigation if an accident results in a
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fatality, causes property loss or damage in excess of $100,000, causes
radiological contamination, results in a serious injury or illness,
releases pollutants, or should be investigated for some other reason. For
each investigation, a specially trained team is dispatched to the site
immediately after the accident. The team investigates the accident and
files a formal report with DOE Headquarters, usually within 45 days. The
report includes recommendations for preventing similar accidents in the
future.
The type of work conducted for each of the 34 accidents surveyed
provides a useful basis for categorizing the results of this review:
o Most of these investigations involved accidents that occurred
during support operations. Support operations include
construction, mining, quarrying, tunnel drilling, and similar
work that does not fall into one the other categories listed
here. DOE investigated 10 accidents related to support
operations, five of which resulted in fatalities.
o DOE investigated seven accidents that occurred during mission
operations. Mission operations include plant production and
related normal operations. No fatalities occurred as a result
of these accidents.
o DOE investigated six accidents associated with maintenance
activities. One of these accidents involved a fatality.
o DOE investigated four accidents related to research and
development (R&D) operations. As with mission operations, none
of these accidents involved a fatality.
o Accidents in the area of air transportation claimed the most
lives. DOE investigated four air transportation accidents that
resulted in 17 fatalities.
o Accidents involving various means of ground transportation
(e.g., cars, trucks, and forklifts), also claimed a number of
lives. DOE investigated three ground transportation accidents,
each of which resulted in a fatality.
Lessons learned
A better awareness of the general level of danger inherent in a
particular activity can help workers and managers take more effective
steps to ensure a safer workplace.
The Observer's overview of Type A and B accident investigations
supports the following conclusions:
o Accidents can occur during any phase of operation.
o The number of fatalities in the area of air transportation is
particularly noteworthy. Of the 26 people who died in accidents
during the period reviewed, 17 were killed in accidents
involving air transportation. The dangerous nature of air
transportation is even more striking when one considers that
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these 17 deaths occurred in the relatively small population of
DOE personnel who traveled by air. Mission operations, by
contrast, involved many more people but did not result in fatal
accidents.
o Ground transportation was also a dangerous activity, claiming
three lives during the period under review.
o Support activities generated the highest number of
investigations and the second highest number of fatalities.
When considering this information, it is important to realize that
nonfatal accidents can be very serious -- workers may incur injuries that
result in permanent disability. A nonfatal accident may also represent a
near miss that could have been fatal under slightly different
circumstances. Thus, although it is important to realize that activities
involving transportation and construction are inherently most dangerous,
there is room to improve safety for all phases of operation at DOE
facilities.