Three Shell Canada workers were examined at a health centre after an arc flash occurred at the corporation’s Scotford chemical plant and oil refinery in northern Alberta, on the afternoon of Sept. 18. Fortunately, there were no serious injuries, according to the company.

“Workers were preparing for a maintenance job in an electrical substation at our Scotford facility when there was an unexpected electrical arc flash,” said Shell Canada spokesperson Cameron Yost, noting that the incident had occurred late in the afternoon.

“Three employees were taken to the health centre as a precaution and were cleared for full duty later that evening,” added Yost.

“We are investigating the cause of the incident.”

Occupational health and safety officials with the Alberta Ministry of Labour are reportedly investigating as well, but the Ministry did not respond to COHSN’s request for comment.

First opened in 1984 and located about 45 kilometres northeast of Edmonton, Shell’s Scotford plant converts bitumen from Alberta’s oilsands into other products. The refinery was the first one to process synthetic crude oil exclusively from the oilsands, according to information from the company website.

The Canadian Centre for Occupational Health and Safety (CCOHS) in Hamilton, Ont. notes on its website that electrical arc flashes can cause serious injuries or worse, such as electrocution, electric shock, burns and falls.

“An arc blast can include a potential pressure wave released from an arc flash. This wave can cause physical injuries, collapse your lungs or create noise that can damage hearing,” CCOHS says. Another common means of injury is “thermal burns from the heat radiated from an electric arc flash.

“Ultraviolet and infrared light emitted from the arc flash can also cause damage to the eyes.”