An employee at Los Alamos National Laboratory was blown off a ladder and severely burned in 2015 after spraying cleaning solutions on parts of a power substation that turned out to be electrified, according to a report on the incident published last week.
After the resulting arc-flash, nine employees were sent to Los Alamos Medical Center on May 2, 2015, according to the Joint Accident Investigation Team report published March 29. Two of those employees were hospitalized while the other seven were evaluated and treated and then released.
The most seriously injured employee, referred to in the report as E1, was performing preventive maintenance in a substation that supplies power to Los Alamos’ Technical Area 53. The maintenance involved “racking out, cleaning, performing conduction and timing measurements, and carrying out high-potential testing on breakers, as well as cleaning the switchgear cubicles,” the report said.
This sort of maintenance is performed in two- and five-year cycles. The entire switchgear was de-energized when maintenance began on May 2, 2015, but once some of the maintenance was completed by Saturday evening, two of the three buses in the switchgear were re-energized to supply power to TA-53.
E1 sprayed cleaning solution between the two energized bus bars, creating a path to ground and resulting in the arc-flash. The arc caused a rapid release of thermal energy, causing severe burns to E1’s hands, forearms, chest, face, head and left rear upper torso, according to the accident report. E1 also received a minor laceration to the back of the head as a result of falling from a ladder.
“Within the relatively confined cubicle space, it is assumed that E1 placed his hands, forearms, chest, and face in close proximity to the energized components of all three phases within Bus B at the time of the accident,” the report said. “Medical assessment of the resulting injuries determined no evidence of direct electrical contact to any skin surface; all burns were caused by exposure to the extreme thermal energy of the arc-flash.”
In critical condition, E1 was transferred to Albuquerque Medical Center Burn Center at the University of New Mexico Hospital in Albuquerque for ongoing treatment,” the report said. There was no evidence of injury to hearing or vision.
A second employee, identified as E2, was admitted to the hospital for observation and treatment of inhalation exposure and released two days later. Two individuals were evaluated for potential smoke inhalation. All others were evaluated, treated, and released.
“The involved personnel reacted effectively and appropriately to ensure that workers were successfully evacuated from the switchgear and moved to a safe location,” the report said. “Appropriate first aid was given to E1.”
The lengthy investigation found the direct cause of the accident was the cleaning fluid sprayed into the air gap between energized switchgear bus and the grounding enclosure. The aerosolized fluid created a path to ground, resulting in an arc-flash. The root cause was less-than-adequate management of control implementation.
