Documents Show Superior Oil Refinery Knew About Valve Issues Years Prior to 2018 Explosion

In an investigative article from Wisconsin Public Radio (WPR), it is revealed that officials at a northwestern Wisconsin oil refinery knew about equipment issues years before a 2018 explosion there, according to Occupational Safety and Health Administration (OSHA) documents.

WPR secured nearly 1,300 pages of documents from OSHA that shed new light on what those officials knew in the days leading up to the explosion at the refinery in Superior, then owned by Husky Energy Inc., as well as what equipment issues they were aware of years earlier. They include problems with a critical valve malfunctioning days before the explosion and documented erosion on that piece of equipment dating back to 2008.

The April 26, 2018, blast injured 36 refinery employees and contractors and forced the evacuation of many of Superior’s 27,000 residents because of black smoke and fears that a tank containing the highly toxic chemical hydrogen fluoride might be compromised.

The refinery was shutting down its fluid catalytic cracking unit when the explosion happened as it prepared for a five-week production break for maintenance. The unit uses heat and a sand-like catalyst to crack or break apart large hydrocarbons of crude oil into smaller molecules to make gasoline and other products.

More information on the report is available from the Milwaukee Journal Sentinel or WPR.