On April 26, 2018, an explosion and subsequent fire occurred at the Husky Energy Oil Refinery in Superior, Wisconsin. What began as an explosion and subsequent fire at the plant at 10:00 AM CST was dealt with accordingly close to noon. However, the explosion had sent debris flying across the refinery; one piece struck an above ground storage tank containing 50,000 barrels of asphalt, which then ignited and sent a thick plume of black smoke into the air. Evacuations were ordered in the city of Superior, including businesses, schools, and a hospital. The fire was extinguished later in the evening, and the evacuation order would be lifted the following morning. 36 refinery employees were treated for injuries resulting from the explosion. There were no fatalities. The U.S. Chemical Safety Board's investigation revealed that there were no safeguards in place to prevent explosions in the event of a shutdown.