On April 26, 2018, an explosion and subsequent fire occurred at the Husky Energy Oil Refinery in Superior, Wisconsin.

An initial explosion was reported at 10:00 AM and was extinguished close to noon, however a piece of debris had hit a storage tank containing asphalt, which ignited after spilling across the refinery, sending a thick plume of black smoke into the air.

Residents who lived 3 miles north, east, and south of the refinery were also ordered to evacuate due to concerns about the change in the direction of the wind forcing the toxic smoke above more homes, and due to concerns about the refinery's hydrofluoric acid tank causing potential further explosions and damage.

The fire was fully extinguished at 7 p.m., however the evacuation order remained in place until 6 am the next day due to concerns regarding the stability of the plant's hydrogen fluoride tank.

"[9] Cenovus put out a statement after the report stating that the refinery is cooperating with the CSB to implement their recommendations into the refinery's rebuild, one of them being "new state-of-the-art slide valves in the Fluid Catalytic Cracking unit with enhanced safeguards such as advanced instrumentation to monitor performance in real-time and ensure the operations and engineering staff can carefully assess performance.

Superior Mayor Jim Paine and Duluth Mayor Emily Larson have publicly come forward expressing disapproval with the plant's use of the chemical, citing multiple safety hazards to the surrounding communities had the HF tank been affected by the fire.

Husky Energy faced a class-action lawsuit against residents who were forced to evacuate their homes, citing a section from the report of the USCSB that stated that their equipment "failed to separate oxygen and hydrocarbons, allowing a flammable mixture to form.

[13] In April 2022, close to the fourth anniversary of the explosion, a group claiming to be a PR firm for Cenovus Energy called "Husky Friends" sent Superior residents postcards and kits containing things such as information about hydrogen fluoride.