An explosion and fire at the Husky Energy refinery in Superior, WI has resulted in at least 10 people being transported to area hospitals. Local news sources reported that 9 of those injured are being treated for non-life-threatening injuries and 1 victim is being treated for “serious blast injuries.” Although initial news sources reported that the fire had been contained and extinguished, the same sources reported that the fire had reignited at about 12:30 PM and that the new fire appeared to involve asphalt storage tanks.
After the initial fire and explosion, Superior officials reported that no “shelter in place” or mandatory evacuation orders had been issued. Following the resurgence of the fire, emergency management agencies issued evacuation orders for all residencies and businesses within a 1-mile radius of the refinery and for a larger area south of the plant. The evacuation orders were related to the presence of heavy black smoke from the second fire and affected, among others, the Superior YMCA and the Nemadji Golf Course. Day and evening classes at Wisconsin Indianhead Technical College (WITC) were cancelled but were expected to resume their normal schedule on Friday.
News broadcasts aired by WKOW television reported that Superior Mayor Jim Paine had identified an “asphalt spill” as the cause of the explosion and fire. The station also reported that work crews from Hunt Electric had been present at the plant and had been performing routine maintenance work that the time of the first explosion. A spokesman for Plumbers and Steam Fitters Local 11 confirmed that it had members onsite who were working for two contractors at the refinery and that the plant was not shut down at the time of the first incident.
According to the Husky Energy website, its Superior refinery processes oil from North Dakota and southern Canada into gasoline, asphalt, diesel and heavy fuel oils. The plant has a processing capacity of about 40,000 barrels per day and employs 180 full-time workers.
Husky Energy purchased the refinery and other “downstream” assets from Calumet Specialty Products in November 2017 for a reported $492 million. At the time the purchase was finalized Calumet was in the process of completing a $30 million upgrade to the facility, which Husky said it planned to complete, but it was unclear whether today’s explosions were linked to that upgrade.
As of this writing, the second fire is under control but is still burning. Disaster management experts state that this is an acceptable course of action when dealing with fires in a chemical plant or refinery in that allowing the fire to burn will eventually exhaust the fire’s fuel supply and, at the same time, will reduce the amount of waste products that could enter the atmosphere or local water supply.
Update April 27, 2018 WBAY television reports that the asphalt tank fire has been extinguished and the previous day’s evacuation orders have been lifted, although the refinery will remain closed indefinitely.
Although it is far too early to reliably identify the cause of the Husky Superior refinery explosion and fire, it is well-known that many refinery/chemical plant accidents occur when such operations are either undergoing routine, scheduled maintenance or immediately after such maintenance when the facility is “brought back online” and production resumes. In the former case, inadequate venting of residual gasses can lead to explosions and fires if a spark is introduced into a supposedly empty processing vessel. In the latter instance, improper installation of electronic monitoring and control systems may cause a “runaway” chemical reaction that produces a fire and explosion. Also, the high temperatures and pressures employed can cause a failure of incorrectly installed pipe fittings or defective welds.
Even though today’s explosion and fire at Husky’s Superior refinery did cause some injuries, none of those injuries were reported to be life-threatening and, fortunately, there were no fatalities. It will be several days before conditions inside the Superior unit will stabilize enough for a thorough investigation of the incident to be completed, officials at Husky’s corporate headquarters and on-the-scene managers have stated that the company is committed to restoring the unit to full production capacity as soon as possible.