According to a recent report from the Washington State Fatality Assessment & Control Evaluation (FACE) Program and the Division of Occupational Safety and Health (DOSH), WA State Dept. of Labor & Industries, two technicians servicing an articulating boom lift in the parking lot of a distribution center under construction recently suffered burns when electricity arced from a power line to the lift. Following is a summary, as reported in bulletin, of the steps that led up to the accident.
A construction contractor had rented the lift and found that it was not working due to a leak in its hydraulic line. They contacted the rental company, which then contacted a hydraulic and industrial hose repair service. The repair service sent two experienced service technicians to repair the lift.
After they repaired the hydraulic line, they decided to test that the repair had been successful. The technicians were focused on their task and did not notice the high-voltage 69kV power transmission line 36 feet above the ground overhead. The day was overcast with intermittent showers, which may have affected their ability to see the power line.
From the ground, one technician operated the lift’s controls to elevate the boom. The other stood behind the lift to check for a hydraulic fluid leak. As the technician raised the boom, it came near to the power line, but did not touch it. Electrical current arced from the line to the lift basket’s wet metal railing and traveled through the lift’s frame into the parking lot asphalt where the technicians were standing. The shirt of the technician standing behind the lift caught fire and he received electrical burn wounds to his upper body and left foot. The other technician received electrical burns to his fingers. Both were hospitalized; one worker returned to work after several days, the other after several weeks.
FACE investigators concluded that, in order to help prevent similar occurrences, employers should train employees who operate aerial lifts:
- To recognize electrical hazards from overhead power lines.
- That electricity can arc, or jump, from a power line to an aerial lift without contact with the line. If any part of the lift gets too close to a power line, an arc can cause electrical current to energize the lift and run through it to the ground. This is especially true when a conductive object, such as a lift’s boom or basket, is wet.
- To be aware that power lines can be difficult to see, and that judging their height from the ground can be difficult, especially on cloudy, showery days when there is low contrast.
For requirements specific to the state of Washington, review the following documents:
- Employers must have the operator survey the area for hazards before using an aerial lift. See WAC 296-869-20035.
- Employers must ensure that operators maintain the minimum safe approach distance to energized power lines. See WAC 296-869-60035(1)(f).
For more information on working too close to overhead power lines, visit the department’s website.