A huge explosion rocked the Husky Energy Oil refinery in Superior, Wisconsin this morning, sending at least six workers to the hospital and causing the evacuation of schools, businesses and hospitals in a 78 square mile area around the refinery. One worker is apparently being treated for “serious blast injuries.” The explosion reportedly occurred in a tank containing crude oil or asphalt
The initial blast shook a nearby golf course, rattled offices in Superior’s business district and sent thick, black smoke into the sky above the refinery, located across the Lake Superior harbor from Duluth. Six of 20 people injured were taken to the hospital, according to the Superior Fire Department.
The initial explosion occurred at 10:06 and another tank caught fire at 3:15 p.m. OSHA will investigate the incident and the Chemical Safety Board has also launched an investigation.
Around 180 people work at the refinery which was built in 1950. It was originally owned by Murphy Oil, which bought it in 1958 and later sold it to Calumet Specialty Products in 2011, which then sold it to Husky last year. The plant was apparently “closed for cleaning” at the time, according to news sources. This may mean that the plant was in “turnaround” where every few years major maintenance is done on the facility. Turnarounds are generally thought to be the most dangerous time of a plant’s operation. A spokeswoman said some of the injured may be employees of the cleaning vendor.
Hydrogen Fluoride Hazards
According to a 2012 report the refinery was required to send to EPA, the refinery also also contains 78,000 pounds of high hazardous hydrogen fluoride (also known as hydrofluoric acid or HF.) According to EPA, a highly toxic and volatile material and one of the most hazardous chemicals used in refineries. If released, HF can form a vapor cloud that can spread and cause organ failure and death in humans at extremely low levels.
While there was no report that the HF tank was involved in the explosion, the CSB last year reported an incident in California where an explosion caused an 80,000 pound chunk of the electrostatic precipitator to rocket 12 stories up before crashing three feet from a tank containing 50,000 pounds of HF.
Environmentalists and safe chemical activists have been urging EPA and OSHA to require refineries and chemical plants to develop “inherently safer” alternatives to extremely hazardous chemicals like HF. At the end of the Obama administration, EPA issued a new regulation requiring paper manufacturing, coal and petroleum products manufacturing and chemical manufacturing to thoroughly evaluate safer technology and alternatives when conducting their Process Hazard Analysis to assess the potential hazards associated with an chemical process. Implementation of inherently safer measures was not mandatory, however.
Even this was too much for the chemical industry and Trump’s EPA administrator Scott Pruitt, however, who suspended the rule for two years last June “to allow the agency to conduct a reconsideration proceeding and to consider other issues that may benefit from additional comment.”
CalOSHA recently issued a new Process Safety Management Standard for refineries that required facilities to conduct a hierarchy of hazard controls analysis to encourage refinery management to implement the most effective safety measures. Measures would be analyzed and documented in priority order, with the most preferred measure being first order inherent safety measures (eliminating a hazard), followed by second order inherent safety measures (changing a process to minimize a hazard). California’s rules go much farther than EPA’s in the area of inherently safer processes.