Utility district cited in arc flash explosion at hydroelectric dam
L&I cited the utility district for five serious violations and for each assessed the maximum penalty of $7,000
The Washington Department of Labor & Industries (L&I) fined Grant County Public Utility District #2 $35,000 for five serious safety violations after investigating an explosion at its Priest Rapids Dam on the Columbia River in Beverly, Wash. Six workers were hospitalized with serious electrical burns after the explosion.
The workers were troubleshooting a mechanical problem with a generator and "did not know that a circuit had been re-energized when they closed a breaker, which caused the high-voltage electrical arc flash explosion," L&I reported, adding that its investigation found that the arc flash could have been prevented if the employer had ensured safety locks and safeguards were used to prevent the breaker from being closed when other parts of the circuit were energized.
The investigation found that:
- The employer did not ensure the use of lock-out/tag-out safety devices to prevent inadvertently closing a breaker that could cause an arc flash.
- Employees were not briefed on the circuit conditions that affected them and exposed them to risk of arc flash burns and electrocution.
- Employees were not aware that the lock-out/tag-out devices had been removed from the circuit.
- One worker was not wearing fire-resistant clothing while working on the hydro-electric equipment.
- The employer did not provide any records to show it was in compliance with the state regulation on protecting workers from injury due to hazardous energy.