Husky Energy Plant Explosion Investigation Update

At approximately 10:00 AM on April 26th an explosion, followed by two fires, struck the Husky Energy Oil Refinery located in Superior WI. In today’s post, the refinery explosion lawyer at the Doan Law Firm presents an update to that post based on the initial findings of the U.S. Chemical Safety Board (CSB).

The Explosion at Husky Energy Oil Refinery

As we previously discussed, on Thursday, April 26th of this year the Huskey Energy oil refinery in Superior WI was preparing for a 5-week shutdown for scheduled maintenance and/or facility upgrade when it was rocked, at about 10:00 AM, by an explosion and fire in the immediate area of that explosion. This fire was extinguished by refinery employees and units of the City of Superior Fire Department. At that time, it was felt that no declaration of an emergency was necessary.

According to an article by Forum News Service that was carried by the Twin Cities (Minneapolis-St. Paul, MN) Pioneer Press a second fire, accompanied by several explosions, created clouds of thick smoke that were observed as carrying several miles beyond the refinery. These clouds prompted the City of Superior to issue a mandatory evacuation order for areas within 2 1/2-mile radius north of the refinery and within a rectangular area 10 miles south of the refinery, based on the direction that the wind was blowing after the second explosions and fires.

After overnight air samplings by the Environmental Protection Agency detected only trace amounts of atmospheric contamination from smoke originating from the refinery, the mandatory evacuation order was lifted as of 6:00 AM Friday (April 27th).

Preliminary investigation report

Note that our initial blog post was based on information gathered from local and regional news sources in the hours after the explosion and fire. Discrepancies between these reports and the later findings by on-scene CSB investigators could be explained by the fact that these news media did not have access to the Husky refinery. Content provided by the author of this blog, in addition to that of the CSB’s preliminary findings, is contained within “[“and “]” symbols.

According to its initial findings, the CSB presented the following facts based on observations made by its investigators:

  • “The refinery was preparing to enter a [planned] 5-week maintenance turnaround, during which time equipment is shut down so that it can be opened, inspected, and repaired as needed. The explosion occurred at approximately 10 a.m. CDT. The initial explosion caused property damage and loss of containment [puncture] of an asphalt tank. The contents of the tank spilled out and the material combusted [caught fire].”
  • “The initial explosion took place within the refinery’s Fluid Catalytic Cracking, or FCC, unit. The FCC unit “cracks” heavy, high boiling point hydrocarbon molecules [crude oil] into smaller molecules with lower boiling points. The main product produced by the FCC unit is gasoline…”
  • “The explosion created a large amount of debris which was scattered in and around the refinery complex. This debris is being collected and stored for future analysis as needed.”


Again, the author of this post admits that the preliminary findings of the CSB are just that: preliminary, and subject to change in the CSB’s final report. Also, the CSB preliminary report is for use by that agency only and may, or may not, be used by other federal agencies such as the Occupational Health and Safety Administration. This is understandable since federal agencies are limited by law as to their jurisdictions and, thus, their investigational authority over different factors that may have contributed to an industrial accident. However, it is known that at least one chemical used in Fluid Catalytic Cracking Units is dangerous to humans: hydrofluoric acid.

Hydrofluoric acid is commonly used in Fluid Catalytic Cracking Units at not only the Husky Superior refinery, but at refineries nationwide. According to the Centers for Disease Control and Prevention (CDC) most industrial exposure to occurs when a victim’s skin is exposed to contact with its liquid form ( hydrofluoric acid) or by inhalation of its active ingredient in its gaseous form, hydrogen fluoride, which is regarded to be the more-dangerous type of exposure.

Exposure to hydrofluoric acid can result in a chemical burn injury to the skin and, less commonly, injury to a victim’s eyes by either direct “splash” contact or by exposure to its gaseous component, hydrogen fluoride gas. More seriously, hydrogen fluoride gas exposure can cause chemical burns to the upper respiratory or, more importantly, to the lungs themselves. Chemical burns of the respiratory system can be very difficult to treat since hydrogen fluoride gas becomes hydrofluoric acid when it encounters the moisture normally present in the trachea and lungs.

The role of a refinery explosion accident lawyer

Fortunately, the explosion and fires at the Husky Superior refinery produced relatively minor or non-life-threatening injuries to plant personnel and no injuries to anyone outside the refinery’s boundaries. Unfortunately, this is not always the case.

Anyone who has been injured by a refinery accident such as a chemical release, explosion, or fire is invited to contact the refinery explosion lawyer at the Doan Law Firm to arrange a free, no obligation, review of the facts in your refinery accident case. Since our free case review does not obligate you to hire our firm, you are free to hire a law firm of your own choosing to represent your injury case. If you should decide that we should manage your refinery accident injury case, we are willing to assume all responsibility in preparing your case for trial in exchange for a percentage of the settlement that we will win for you.