WorkSafeBC says it has fined two companies a total of $48,000 after an explosion at an oil and gas facility in Dawson Creek, B.C., injured two workers.

According to WorkSafe inspection reports, on June 24, Key Energy was welding at a facility operated by Secure Energy Services that accepts oilfield waste.

The work safety watchdog says both companies failed to take the proper precautions before allowing welding above a tank containing flammable chemicals.

A WorkSafe inspector also reports welders did not use the appropriate equipment to detect flammable gas or vapours in the air before the explosion.

WorkSafe fined Key Energy about $6,000 and Secure Energy Services about $42,000 and required both companies to offer workers proper training and revise risk assessment and safety practices.

Secure Energy Services and Key Energy did not respond to requests for comment.

WorkSafe says the companies were doing maintenance on a building that held a shale shaker, which separates solids from drilling fluid. The shaker’s tank often holds flammable chemicals.

On the day of the explosion, two workers were installing safety chains above the tank.

According to inspection reports, workers are required to use four head monitors to detect several risks, including the concentration of flammable gas or vapours in the air.

Instead, a Key Energy worker took a monitor off a pump and reached into the tank with their arm. Key Energy did not ensure workers wore personal monitors, a WorkSafe inspector said.

WorkSafe said the employer was required to ensure no flammable chemicals were left in the shaker before the welding work. There were no other sources of fuel for the explosion at the worksite, an inspector said.

Another worker at the site reported seeing flames coming from the shaker before an explosion blew the lid off the shaker, lifting the floor grating.

B.C. Emergency Health Services said just before noon on June 24, paramedics took two patients from the 6400 block of Rolla Road to the hospital.

Inspection reports show both companies have complied with orders to create proper safety procedures for hot work and maintenance near the shaker.