According to the Bureau of Labor
Statistics, job-related electrocutions accounted for 5
percent of worker deaths in
1996.2 Electrical accidents
are a continuing safety issue at DOE facilities. They have
caused several fatalities and many serious injuries. EH
engineers classified over 800 hazardous electrical
occurrences by voltage, type of occurrence, location,
equipment causing the occurrence, and equipment damaged by
the occurrence.
The number of electrical occurrences per 200,000 hours
worked is shown in Figure 1. The rate of electrical
occurrences per 200,000 hours worked has increased an
average of 6 percent since 1991.
EH engineers classified electrical events as hazardous if
they involved (1) shocks or other injuries, (2) electric
arcs or other short circuits, (3) electrical fires or
overheating, (4) damaged energized cables, (5) electrical
lockout/tagout procedure violations, or (6) exposure of
electrical equipment to water. Some occurrences were counted
in several categories. Nearly one-third of all occurrences
involved short circuits; nearly one-quarter involved shocks;
and nearly one-quarter involved damaged cables. The
distribution of electrical occurrence types is shown in
Figure 2.
The types of equipment involved in creating most
electrical hazards fall into three categories.
The most common voltage involved in these occurrences was
120 volts. When compared to the total number of occurrences
at each voltage, significantly more shocks involved voltages
of 120 volts and near 1,000 volts; significantly more
injuries involved voltages near 1,000 volts and near 4,160
volts. The voltage distributions for all hazardous
electrical occurrences, shocks, and injuries are shown in
Figure 5.
On January 14, 1987, an electrician at
Rocky Flats received fatal burns from an electrical
arc-flash. He was working on a 2,400-volt, draw-out,
fused-contactor assembly that was part of a motor starter.
He defeated a safety interlock in violation of procedures
and used a digital multimeter with an operating range of 500
volts to attempt measurements on the 2,400-volt system. The
multimeter exploded, causing an electric arc that resulted
in the electrician sustaining massive burns from the
super-heated air. There was no indication that the
electrician received an electrical shock or that current
passed through his body. The scene of the fatality is shown
in Figure 6.3
Investigators identified several factors that contributed
to the accident. They determined that the starter-door
interlock was easily defeated when the door was open and
that the electrician was not adequately motivated to follow
safety procedures. He had not received any safety training
after he became a journeyman electrician and did not
recognize the magnitude of the hazard.
Figure 6. Scene of Fatal Accident at Rocky
Flats
On April 25, 1997, a Bonneville Power Administration
subcontract electrician was fatally electrocuted when he
came in direct contact with a de-energized, 230-kilovolt
transmission line conductor that carried an induced voltage.
A 287-kilovolt line, 125 feet north of and parallel to the
line on which the accident occurred, was operating at the
time of the accident. Accident investigators determined that
the conductor might have carried over 4 kilovolts from
inductive coupling with the energized line. When the
electrician grounded the conductor, a 60-hertz discharge
current of over 125 milliamperes flowed through his body.
The accident occurred while the electrician was
attempting to remove a gripper from the conductor. A
reenactment of the accident is shown in Figure
7.4
Investigators found that the portable protective grounds
used at the accident scene were not properly secured at the
ground clamp end. Tightening devices were only finger-tight,
and internal copper wires were frayed at the ends and
appeared to be smashed. Paint underneath the ground clamps
had not been removed to allow for the metal-to-metal contact
required for proper grounding. After the accident,
investigators found the conductor end of the personal ground
attached to the rail from the inside, raising the question
of whether the ground had been in place at the time of the
accident.
Figure 7. Reenactment of Fatal Transmission
Line Accident at the Bonneville Power Administration
Investigators also found that, because the ground was
muddy, the aerial lift was hauled into place and was not
positioned correctly. The electrician could not stand in the
workbasket of the lift normally, but had to stand on the
middle rail of the basket. This may have contributed to the
lack of proper grounding. There was no evidence that the
electrician had been trained on parallel line induction and
other hazards associated with high-voltage transmission
lines. Investigators also determined that the work practices
of the subcontractor were not the same as in the safety plan
submitted. On August 22, 1994, a lineman at the Western Area
Power Authority was fatally electrocuted while trimming a
tree from the bucket of an aerial manlift adjacent to a
230-kilovolt transmission line near Redding, California. The
lineman cut a branch of a eucalyptus tree that was leaning
toward the transmission line. The branch fell across the
transmission line, placing the lineman in the current path
and electrocuting him.5
Investigators determined that the crew completed an oral
job hazard analysis and determined the work procedures that
would be used. They agreed that the lineman would attach a
winch line to the top section of the tree, descend about 8
feet in the bucket, and cut the tree. He started the job
and, after conferring with the rest of the crew, removed a
large limb that was leaning away from the line without using
the winch line. He then started cutting small branches
without a winch line, violating the procedure. He cut three
branches successfully, while crew members yelled at him to
stop. The fourth branch, about 16 feet long and 1-1/2 inches
in diameter, fell across the line, suspended between the
line and the holding wood. As the branch continued to fall,
an electric arc developed between the line and the branch.
The branch contacted the lineman, allowing current to flow
through him.
A tree-felling expert analyzed the technique used by the
crew. He stated that the accident would not have occurred if
the agreed-on procedure had been followed. Investigators
also found that the lineman violated safe working distance
requirements while cutting the last branch and that it was
an error in judgement to cut a branch that was leaning
toward the conductor. This was the probable direct cause of
the accident. The root causes were "ineffective management
oversight policy" and "ineffective Occupational Safety and
Health Program management." Investigators identified the
following contributing causes: "Deviation from the
previously agreed upon work plan"; "Western's failure to
implement previous tree-felling accident judgement of need,
'Western must improve management and oversight of
transmission line right-of-way maintenance plans'"; and
"failure to fully implement its [Western's] existing
[right-of-way] management policy . . . to permanently remove
potentially hazardous trees."
On January 17, 1996, at the Los Alamos National
Laboratory, a mason tender received a severe electrical
shock that resulted in serious burns and cardiac arrest when
the jackhammer he was operating contacted an energized
13.2-kilovolt electrical cable. His injuries resulted in an
extended coma, and he is currently in a long-term care
facility. A Type A Accident Investigation Board determined
that significant safety deficiencies in the safety
management program at Los Alamos contributed to this
accident. They also determined that there was inadequate
line management accountability and ownership, as well as an
inability to learn from previous incidents to prevent their
recurrence.6
The laborer and a foreman were excavating for
installation of a sump pump in the building basement. The
project required them to remove a section of the concrete
floor and dig a 3-foot-deep hole in the southwest corner of
the basement. The foreman and laborer removed the section of
concrete and began removing the earth. They were wearing
personal protective equipment consisting of gloves,
safety-toe shoes, hard hats, and eye and ear protection. The
laborer and the foreman were taking turns using a jackhammer
and shovel to remove the earth. The laborer gave the foreman
the shovel and started using the jackhammer. Shortly after
that the foreman observed the laborer holding the jackhammer
and shaking; then he heard an explosion. When the laborer
started to fall into the hole, the foreman pulled him
partially out and ran for help. The foreman suffered from
smoke inhalation and was released that day from the Los
Alamos Medical Center; the laborer was later moved from the
Center to a hospital in Albuquerque. He remains in a coma
after two and a half years. A close-up of the damage to the
cable is shown in Figure 8.
Figure 8. Close-up of Damage to 13.2-Kilovolt
Cable at Los Alamos
Facility personnel performed construction work using a
maintenance process. This resulted in there being no
mechanisms in place to capture modifications made to a
Category 3 nuclear facility. Investigators determined that
there were no plans to update the as-built drawings for the
work being performed and that modifications were being
driven by time constraints to meet an Environmental
Protection Agency administrative order deadline of October
1996. Ad hoc procedures were created without the benefit of
required detailed reviews.
On June 17, 1994, at Oak Ridge, an electrical arc blast
occurred when a No. 6 grounding conductor came in contact
with one of the energized phase lugs of the main breaker
inside a 480-volt cabinet. Accident investigators determined
that the arc spread from phase-to-ground to phase-to-phase,
producing an arc blast and loud explosion. The arc blast
resulted in severe (third-degree) burns to the neck, arms,
and torso of the electrician handling the ground wire. The
electrician, although experienced, had not locked out or
tagged out the incoming power to the panel and had not taken
compensatory measures for work on or near energized
equipment. The damaged breaker is shown in Figure
9.7
Figure 9. Breaker Involved in Arc Blast Resulting in
Third-Degree Burns
Investigators found that after a series of electrical
occurrences, Martin Marietta Energy Services (MMES) had
instituted an electrical stand-down in January 1994 to train
workers on electrical safety and upgraded procedures. MMES
management did not provide adequate follow-up to ensure that
the new procedures had been accepted and properly
implemented. They also found that the electricians had
sufficient training to perform their duties, but did not
apply the training that addressed safe work practices. The
training was not skill-based.
Investigators also found that there was no formal,
approved procedure for performing job hazard analysis or for
providing sufficient review of work packages by industrial
safety representatives. The work package did not contain
detailed work instructions, maintenance verification points,
provisions for personal protective equipment, or details
regarding the lockout/tagout to be performed by the workers.
Neither the supervisor nor the customer documented their
reviews of the work package. Investigators found that the
plant procedure used did not meet the intent of OSHA
regulations for using personal protective equipment when
working near voltages over 300 volts
They also found that supervision was inadequate and
lessons learned from previous occurrences were not
implemented.
In addition to the fatal accidents, several serious
electrical events occurred during the first half of fiscal
year 1998. Following is a brief description of some of the
events.
On October 22, 1997, two electricians attempting to
provide temporary power for lighting and heat received
second- and third-degree burns in an electrical flashover
incident at Fermi National Accelerator Laboratory.
On January 20, 1998, an apprentice lineman supporting the
Western Area Power Administration received electrical burns
after coming in contact with an energized 12.47-kilovolt bus
at a power substation near Phoenix, Arizona.
On January 16, 1998, an employee was hospitalized at
Sandia National Laboratory after receiving an electrical
shock between his index finger and thumb while removing a
banana-jack connection while performing test circuit
diagnostics.
