On April 26, Superior made world headlines when an explosion at the Husky Energy oil refinery resulted in evacuations up to ten miles away. Although located in an industrial part of town, the refinery is within a mile of a residential area.
At around 10 a.m., an explosion caused an asphalt fire and a momentary loss of electrical power. When burned, asphalt emits chemicals that continue to hang around long after the smoke dissipates. The Environmental Protection Agency states that these gaseous chemicals contain volatile organic compounds, which can cause dizziness, nausea, and, in greater exposure, liver damage and cancer.
The prevailing winds that day were in a southerly direction, away from Duluth and most of Superior (although due to close proximity to the refinery, much of Superior was evacuated anyway). The Superior Fire Department sent all three of its engine companies to the explosion site. Duluth sent one, and several other nearby municipalities sent firefighters to assist.
The refinery goes back to the early 1950s, and has changed ownership several times, most recently when Husky Energy bought it from Calumet for close to half a billion dollars. It’s the only oil refinery in Wisconsin. One tank in the refinery, but not at the point of explosion, contained hydrogen fluoride, a dangerous chemical used to process high octane gasoline.
Fortunately, the tank containing hydrogen fluoride was unaffected by the explosion and fire, but a worst-case scenario would place tens of thousands of people in immediate danger.
Hydrogen fluoride is commonly used in refrigerants, herbicides, fluorescent light bulbs, electrical compounds, aluminum, plastics and pharmaceuticals. If it gets on the skin, it can cause severe burns and tissue damage. Inhalation damages the lungs and can cause pulmonary edema, swelling and fluid accumulation in the lungs. It can quickly cause blindness by damaging the retinas. Even minor contact can be fatal.
Hydrogen fluoride is used for turning crude oil into gasoline. Close to a third of all refineries in the U.S. use it, according to the investigator in charge of the chemical safety board. Less than a week after the explosion, the Environmental Protection Agency concluded that no elevated levels of anything toxic were found during monitoring.
The Monday after the explosion, Wisconsin Governor Scott Walker toured the refinery. As of May 11, the cause of the explosion, which occurred in the fluid catalytic cracking unit, is still under investigation. The explosion took place shortly before a five-week shutdown for maintenance. Sixteen workers were injured from the blast.
A stretch of Hill Avenue, which runs along the western side of the refinery, was closed for much of the day. Other Superior facilities near the refinery are the University of Wisconsin Superior, Wisconsin Indianhead Technical College and the Douglas County Y.M.C.A.
Both Superior Mayor Jim Paine and Duluth Mayor Emily Larson have asked Husky to use a safer alternative to hydrogen fluoride, but Husky has so far refused.
Look for a slightly warmer and drier than average June this year, despite rather common thunderstorms this month. Cool temperatures mid-June will yield to hot temps as we approach July.