Surveilance video captures the initial cat cracker explosion on April 26 that rocked the Husky refinery in Superior, WI. - Photos provided by Superior Fire Department

Surveilance video captures the initial cat cracker explosion on April 26 that rocked the Husky refinery in Superior, WI.

Photos provided by Superior Fire Department

Rather than race to the scene, Superior, Wisconsin, Fire Chief Steve Panger went straight to fire department headquarters when an April 26 refinery explosion rocked the community. Planning for an emergency response on the scale required that day had long been in place, he said.

“I knew we’d have callback crews of off-duty personnel reporting immediately,” Panger said. “My immediate job was to manage those crews and cover the fire stations emptied by the initial response to the blast.”

As the incident progressed and the stations were backfilled, Panger would move to the command post already set up by Husky Energy personnel.

The explosion in a fluid catalytic cracking unit triggered an ongoing fire at the 38,000 bpd refinery that burned for the next eight hours, forcing an evacuation of Superior, population 27,000. Those residents were not allowed to return until the following morning.

At the time of the blast, the refinery was busy preparing for a five-week turnaround for maintenance. Nearly 150 contract workers were on site, Panger said.

 “By good fortune, most were in blast-proof areas on break,” he said. “Some were injured but no one was killed.”

Only one person required hospitalization. At least 10 others were treated and sent home.

First Response


Two firefighting organizations initially responded to the refinery explosion – the Superior Fire Department and the refinery’s own emergency response team. Beyond the refinery, Superior firefighters carry the heavy responsibility of protecting a great deal of industrial activity.

“We’re right on the tip of Lake Superior,” Panger said. “We are very much a transportation hub.”

The port maintained by the twin cities of Superior and Duluth is the largest on the Great Lakes. In its busiest year the port shipped 41.4 million metric tons of goods. Adding to SFD’s fire protection burden is a 550-acre crude oil distribution terminal through which more than 20 percent of all daily U.S. crude imports pass.

“We also have shipping for coal, lime, grain and iron ore through here,” Panger said.

He administers a fire department consisting of 37 full-time firefighters divided between three fire stations. One engine company operates out of each station with four responders per shift.

The refinery ERT consisted of process operators and other personnel cross trained to handle emergency response, Panger said. Apparatus available to the ERT includes an engine and a 3,000-gallon foam tender.

What unites the city and area industrial firefighters such as the refinery ERT is a public-private partnership known as the Superior Petroleum Partnership, Panger said. Founded in 2013, it replaced an earlier mutual aid group that had fallen by the wayside out of neglect.

“Our responders train together,” Panger said. “We also do emergency planning together. We coordinate our training and our equipment. Obviously it’s pretty critical that we train together if we’re going to work together.”

While each facility maintains its own emergency response plan, the partnership coordinates a collective response plan that brings the facilities together in an emergency, he said. Acting together, the firefighters have mastered the intricacies of a unified response under the Incident Command System.

The partnership’s joint training schedule includes annual trips to Texas to attend the Williams Fire and Hazard Control XTREME foam firefighting school at Brayton Fire Training Field in College Station and training with the Refinery Terminal Fire Company in Corpus Christi.

“Through the partnership we work together and share resources,” Panger said. “We’ve created a cache of resources to draw from.”

For the Petroleum Partnership, the acid test of this combined effort came suddenly in April.

Catalytic Cracking Unit

Firefighters use surveilance drones borrowed from police. -

Firefighters use surveilance drones borrowed from police.

U.S. Chemical Safety Board investigators report that the initial explosion at the refinery was in a gasoline producing 13,000 barrel per day fluid catalytic cracking unit (FCC), also known as a cat cracker. The FCC unit “cracks” heavy, high boiling point hydrocarbon molecules into smaller molecules, reducing the boiling point to something more useful.

At 10:06 a.m., only moments after the blast, the Superior Fire Department issued its first alarm. Even though the closest station was less than three minutes away, the refinery ERT had the resulting fire under control even before municipal responders arrived, Panger said.

Instead, the municipal responders turned their efforts towards helping the injured, he said.

“This emergency really divided into two parts,” he said. “The initial fire was quickly extinguished and the effort then turned into a mass injury situation. We ended up with six people transported and some others that were evaluated on the scene but didn’t require transport.”

Unfortunately, the second part of the emergency proved more of a test for the Petroleum Partnership. A piece of shrapnel from the cat cracker explosion pierced a full asphalt tank nearby. Hot asphalt under pressure projected from the resulting hole, some of it landing beyond the diked area surrounding the cat cracker.

“It was spreading across the refinery,” Panger said. “The task of containment was pretty difficult.”

For what might have been as much as an hour beyond the initial blast the asphalt spill continued to spread.

“Eventually it flashed,” Panger said. “Honestly, by the size and heat of this thing everybody knew it was going to be a long, long fire.”

Soon pressure valves everywhere opened and began screeching. Pressure inside the leaking asphalt tank built to the point that it blew out one side, Panger said. The firefighters – industrial and municipal – fell back to a defensive position to formulate a new plan.

“Husky had set up our incident command at their administrative building,” Panger said. “When the second fire touched off we had to move it because it was in the evacuation zone. We had to move it to another part of town on the north side.”

Wind direction forced evacuations over an area that expanded six miles wide at its furthest point more than 10 miles south of the refinery, he said.

“That’s not a densely populated area,” Panger said. “If smoke had gone north, it would have been blowing through Duluth.”

Limited Options

Other than to confine the blaze to one tank, the options for firefighting were extremely limited. Settling in for the long haul, the city and the ERT established a rehab rotation that kept about 25 of the available firefighters in action at any one time.

Both pieces of ERT apparatus were brought to bear against the flames. The city contributed a pumper and a dual tote trailer to the foam delivery effort.

“We had a dual tote that we were using,” Panger said. “They had some hand lines and some fixed monitors in use.”

To control the runoff, particularly any contaminated by fire foam, oil booms were used, he said. Everything captured was pumped back into a fire pond that had been established.

“There is a creek that runs through that area that eventually goes into Lake Superior,” Panger said. “They were closely monitoring that.”

Thick smoke at ground level made it difficult to understand the spread of the fire throughout the refinery, he said. Fortunately, the Superior police department came equipped with a unique tool in its arsenal -- aerial drones used for video surveillance.

“Once we were able to get a good look at the fire we could make a plan about how to attack it,” Panger said.

Between the two major industrial concerns in Superior, firefighters were able to amass nearly 25,000 gallons of foam concentrate. But even twice that amount would have been useless against the blistering heat involved.   

“It was simply too hot to start applying foam,” Panger said. “It was literally just burning off. So we had to try and control the perimeter while some of the product burned off.”

Eight hours after the initial blast, firefighters extinguished the diminishing fire. Only 5,000 gallons of the foam concentrate stockpiled was used.

Investigative Aftermath

For weeks afterward, Husky maintained its command post to aid with multiple ongoing investigations and damage assessments.

 “People still have concerns about the environmental damage,” Panger said. “People are pushing for information about collecting the fallout in their yards. Claims for damage are being processed.”

The refinery remains closed. One immediate economic impact on the community is a rate increase proposed by the local electrical utility to compensate for the loss of net income from refinery operations.

As for the firefighters involved, the refinery fire response is continuing to be rehashed in multiple after action reports.

“We just wrapped up our critique Wednesday,” Panger said. “The ERT had one on Friday. We plan to get together soon to review the operations side of the response.”