Human error and safety lapses led to Grant PUD employees being injured at Priest Rapids Dam last October. EC&M reported the story on Oct. 9, in which the explosion at the hydroelectric dam on the Columbia River injured six workers.
The Grant PUD recently released the findings of its investigation of what happened when the employees were hospitalized with burns suffered in an arc flash. The arc flash was because a circuit "breaker was manually slow closed while energized with unit P08 in a stopped position," according to a Grant PUD document.
According to FiberOne News, investigators conducted a root-cause analysis and determined a series of human and process errors were involved in the accident, including:
- Leadership not adequately setting and enforcing safety expectations
- On-site leaders not controlling the work activities or ensuring that energy sources were isolated prior to allowing work on the breaker
- No pre-job brief was performed to outline known safety hazards within the work environment
- Employees had a knowledge gap of how the breaker operated, the potential risks associated with the equipment, and how it would function under the conditions they experienced
- The employees working on the breaker did not verify that it was safe to work on before they began their work
The circuit breaker is on the dam’s No. 8 generator. Each of the dam’s 10 generators is equipped with the same type of circuit breakers.