In this episode, Jo and Molly discuss the CSB's final investigation report on the 2018 explosion and asphalt fire at the Husky Superior Refinery in Superior, Wisconsin. During a shutdown on April 26, 2018, flammable material got into a section of equipment which contained oxygen and ignited, causing two vessels to explode into fragments, one of which punctured a nearby asphalt storage tank. The resulting asphalt spill spread through several production units and then caught fire. Fortunately there were no casualties, but the incident did result in the injury of 36 refinery and contract workers, the evacuation of more than 2,500 residents, $550 million in property damage, and the release of 39,000 pounds of a flammable hydrocarbon vapor mixture.  The CSB released an animated video detailing the events in December 2019, and then released its final report on the incident in December 2022. Today, we provide some background details, delve more into what happened, and cover how the refinery's shutdown, lack of knowledge, and inadequate PHA contributed to the event. Additionally, we'll cover all of the CSB's recommendations, which include recommendations addressed to the refinery, the Cenovus Corporation, OSHA, EPA, API, and Honeywell UOP. Finally, we'll cover five of our own big process safety takeaways from the incident, related to PSI, operating procedures and training, emergency response, learning from industry and the past, and the hazards of transient operations. 

Find the CSB's final report here. 

Find the CSB's video on the incident here. 

Find additional information about the CSB's investigation here.