Chemical Safety Board Shares Video of Superior Refinery Explosion

The US Chemical Safety and Hazard Investigation Board (CSB) released a new safety video on its investigation into the April 2018 explosion and fire at the Husky Superior Refinery in Superior, WI.

The incident injured 36 workers, caused roughly $550 million in damage to the facility, and released 39,000 lb of flammable hydrocarbon vapor into the air. More than 2,500 residents of Superior were evacuated from their homes, and the City of Duluth, MN, issued a shelter in place order as well. Duluth is around 7.5 miles to the north of Superior.

At the time of the incident, the Superior Refinery was owned by Husky Energy, which had purchased the refinery less than six months earlier in November 2017. In 2021, Husky Energy merged with Cenovus Energy.

The incident at the Superior Refinery occurred when the refinery was shutting down its fluid catalytic cracking (FCC) unit to perform planned maintenance. Two vessels within the FCC unit exploded sending debris flying into the air. One piece traveled about 200 feet and hit a large aboveground storage tank, puncturing the side of the tank, and releasing hot asphalt. The asphalt later ignited causing a huge fire.

The CSB's video includes an animation of the series of events leading to the incident, and interviews with both CSB’s Chairperson Steve Owens and Lead Investigator, Melike Yersiz.