Feds: Husky refinery blast could have been prevented

Federal officials say a massive refinery explosion in Superior, Wis., in April could have been prevented if the plant's equipment had been properly maintained.

The Occupational Safety and Health Administration cited Husky Energy for failing to control the use and release of highly hazardous chemicals after an explosion and fire injured several employees.

"Ensuring the mechanical integrity of critical equipment used during the refinery shutdown operation could have prevented this incident," OSHA Eau Claire Area Office Director Mark Hysell said in a statement, adding that the refinery is cooperating with OSHA to put in place a "comprehensive process safety management program" before restarting production.

The company was cited for eight serious violations and faces more than $80,000 in proposed penalties. It has 15 days to respond to the citations.

The April explosion and subsequent fires sent a huge smoke plume into the air and forced the evacuation of thousands of nearby residents.

In a preliminary report released in August, investigators said a failed valve caused the initial explosion, which punctured an asphalt tank and threatened a tank of hydrogen fluoride, a highly toxic chemical.