California NURSE Project
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SUMMARY : CASE
192-036-01
A tree
trimmer was pruning walnut trees in an orchard. He used a
lift bucket (a "cherry picker") attached to a mobile platform,
which he could raise, lower and move along the rows of trees
while standing in the bucket. At the edge of the orchard,
high voltage power lines crossed over the last row of trees
just above the tree tops. The power company was usually called
in to trim these trees.
However,
on this day the worker began pruning the last row of trees.
He raised his lift bucket to the top of one tree. His pruning
shears touched the power line and he was electrocuted. Although
co-workers pulled the lift bucket and platform away from the
power lines with a truck, the worker died instantly. His body
was badly burned.
How
could this death have been prevented?
- Hold
safety meetings before every shift, warning workers of dangers
in their area.
- Ask
the power company to shut off power to lines in the work
area, instead of expecting workers to avoid the lines.
- Work
as a team. Other tree trimmers in the orchard should be
on the look-out for danger.
- Mark
dangerous areas for employees to avoid, such as trees near
power lines.
- Use
tree trimmers who are specially trained to work near power
lines.
BACKGROUND
On April
1, 1992, at 3:15 p.m., the California Occupational Safety
and Health Administration (Cal/OSHA) district compliance office
was notified by an orchard owner of an electrocution in a
walnut orchard. This fatal injury occurred at approximately
2:20 p.m. earlier that day, when a 38 year-old male Hispanic
tree trimmer was electrocuted while pruning walnut trees.
Cal/OSHA
notified NURSE Project staff of the incident on April 9, 1992.
A Senior Safety Engineer from the NURSE project conducted
an on-site investigation on June 2, 1992, and July 1, 1992
and discussed the incident with the farm owner and crew foreman.
NURSE staff reviewed the medical examiner/coroner records
and the Cal/OSHA investigation report.
This
electrocution occurred on a family-owned farm of 1,000 acres,
of which about half are planted in tree fruit and nuts and
half in cotton. Approximately 300 casual (1 to 12 weeks per
year) farm workers are employed by the farm during peak harvest
season, and 15 workers are employed year-around. Cal/OSHA
investigated the incident on April 6, 1992, and found the
employer's safety program to be in compliance with Title 8
California Code of Regulations 3203 -- Injury and Illness
Prevention Program. (As of July 1, 1991 the State of California
requires all employers to have a written seven point injury
prevention program: designated safety person responsible for
implementing the program; mode for ensuring employee compliance;
hazard communication; hazard evaluation through periodic inspections;
injury investigation procedures; intervention process for
correcting hazards; and a health and safety program.)
The
tree trimmer had worked on this farm for several years as
the foreman of a 30-worker crew, but then had returned to
his home in Mexico. He returned to California and was hired
in December, 1991 to prune trees in the orchards during the
next spring season. He received two days of safety training
at that time. Current farm safety policy includes tailgate
safety meetings held every ten days. (Tailgate safety meetings
are brief talks on safety practices by the foreman or supervisor
at the work site before the day's work begins.) The employer
noted that the tree trimmer had been warned of the presence
of the power lines during the initial safety training in December,
1991. During the pruning season last spring, the power company
had trimmed the trees near the power lines.
INCIDENT
On April
1, 1992, at approximately 2:20 p.m., a tree trimmer was pruning
walnut trees using a mobile lift bucket. The lift bucket is
mounted on a platform that has a tricycle-type configuration,
with dual wheels on each of the three axle points. One set
of wheels, in the rear, steers the platform. The wheels in
the front are used to move the unit. A diesel engine in the
base of the platform powers the drive wheels and the hydraulic
system. The control system for the hydraulic lift and the
power system for the mobile platform are in the lift bucket,
enabling the driver to stand in the bucket and operate the
controls that raise and lower the bucket, and move the platform.
Using mobile lift buckets for pruning eliminates the use of
ladders and is more efficient. This lift bucket was not insulated
because it was not intended for use around high voltage power
lines. Therefore, the lift bucket was incapable of preventing
electrical current from flowing through it to the ground.
At the
time of this incident, the fatally injured tree trimmer and
one other tree trimmer were working from two mobile buckets
in the orchard. A 12,000 volt power line (30 feet and 3 inches
above the ground) runs parallel and crosses the last row of
trees (see diagram). At the time of the investigation, tree
branches were observed to be touching the power line.
The
tree trimmer was pruning the last row of trees adjacent to
the roadway with the power lines over his head. The worker
trimmed one side of the tree, then moved the platform into
the roadway on the far side of the tree to prune the other
side. He raised the bucket approximately 25 feet high (as
high as the bucket could go) and lifted his pruning shears
over his head. His shears then came into contact with the
high voltage power line. Upon contact with the power line,
a path-to- ground circuit was established and electricity
flowed through the pruning shears, his body, and down to the
ground through the platform.
Other
employees on the farm used a truck to pull the mobile platform
away from the power lines and lower the lift bucket. Farm
employees also called 911, with the fire and ambulance service,
the county sheriff and the coroner's office all responding.
The coroner noted the tree trimmer was lying on the ground
under the tree where he had been working, and pronounced him
dead at 2:40 p.m.
The
deceased tree trimmer had deep and extensive abdominal burns.
These burns corresponded to clothing burns and burns on the
plastic bumper of the inside edge of the lift bucket where
he had been leaning. There were also burns on his thumbs and
fingers, the front left side of his chest, his right thigh,
right shin, and toes. The metal shaft and plastic handle of
the pruning shears were blackened where he had been holding
them. The boom (neck leading from the platform to the bucket)
of the lift bucket showed electrical discharge markings such
as blackened and peeling paint, and two of the six wheels
had electrical burns down the side with the ground next to
them burned.
The
coroner reported the cause of death as cardiac arrest and
arrhythmia due to electrocution with extensive thermoelectric
burns.
PREVENTION STRATEGIES
- Employers
should keep the work environment free of hazards. The presence
of high voltage power lines is a hazard for any workers
performing their routine work tasks. If the tree trimmer
was going to be working near these lines, the power company
should have been notified and shut off power during the
pruning activity. If the lines had been de-energized or
covered with insulated sleeves, the tree trimmer would not
have been electrocuted when his pruning shears contacted
the lines.
- Workers
who are working as a team or in the same area need to be
sure that there is constant communication and visual contact
among themselves. In this incident, two tree trimmers were
working in the same orchard. If there had been communication
between them, one of the tree trimmers may have warned the
other that they were not supposed to work in the row near
the power lines.
- Employers
should have tailgate safety meetings prior to every work
shift. The foreman should re-enforce the importance of safety
procedures at the work site prior to starting the work day.
Emphasis should be on pointing out specific hazards related
to their tasks and ensuring that employees understand that
safety procedures must be followed to prevent injuries.
If this worker had been instructed earlier that day that
he should not trim the trees next to the power line, he
might not have attempted to do so.
- Employers
should identify and mark all hazards in the work environment.
In this incident, there were no warning signs placed on
trees which were close to the power lines. If these trees
in the last row (near the power lines) had been marked with
highly visible paint, perhaps the tree trimmer would have
been warned that he was in the vicinity of the high voltage
lines. There was also no warning sign on the mobile work
platform saying that equipment should not be operated within
ten feet of the power line*. Originally the mobile platform
had a manufacturer's warning sign, but it had been removed
when a heater was added by the employer. * Title 8 California
Code of Regulations 2947: The owner..shall post and maintain
in plain view of the operator and driver on each crane,
derrick...a durable warning sign legible at 12 feet reading:
"Unlawful to Operate This Equipment Within 10 Feet Of High
Voltage Lines of 50,000 Volts or Less."
- Employers
and foremen should never allow their employees to perform
work that they have not been specifically trained for or
for which they do not have protective equipment. Working
in the vicinity of high voltage power lines requires specialized
equipment and training. Qualified line clearance tree trimmers
are specially trained (with eighteen months of experience
and on-the-job training) for working in the vicinity of
power lines. If the farm owner had hired a qualified line
clearance tree trimmer to perform this task, the worker's
death might have been prevented.
FURTHER INFORMATION
For further
information concerning this incident or other agriculture-related
injuries, please contact:
NURSE Project
California Occupational Health Program
Berkeley
office:
2151 Berkeley Way, Annex 11
Berkeley, California 94704
(510) 849-5150
Fresno office:
1111 Fulton Mall, Suite 212
Fresno, California 93721
(209) 233-1267
Salinas
office:
1000 South Main St., Suite 306
Salinas, California 93901
(408) 757-2892
Disclaimer
and Reproduction Information: Information in NASD does not
represent NIOSH policy. Information included in NASD appears
by permission of the author and/or copyright holder. More
NASD Review: 04/2002
This
document,
CDHS(COHP)-FI-92-005-12
,
was extracted from a series of the Nurses Using Rural Sentinal
Events (NURSE) project, conducted by the California Occupational
Health Program of the California Department of Health Services,
in conjunction with the National Institute for Occupational
Safety and Health. Publication date: August 1992.
The NURSE (Nurses Using Rural Sentinel Events) project is
conducted by the California Occupational Health Program
of the California Department of Health Services, in conjunction
with the National Institute for Occupational Safety and
Health. The program's goal is to prevent occupational injuries
associated with agriculture. Injuries are reported by hospitals,
emergency medical services, clinics, medical examiners,
and coroners. Selected cases are followed up by conducting
interviews of injured workers, co-workers, employers, and
others involved in the incident. An on-site safety investigation
is also conducted. These investigations provide detailed
information on the worker, the work environment, and the
potential risk factors resulting in the injury. Each investigation
concludes with specific recommendations designed to prevent
injuries, for the use of employers, workers, and others
concerned about health and safety in agriculture.
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