A series of explosions and fires rocked the Husky Energy oil refinery in Superior Thursday, sending a black plume of acrid smoke across the city, forcing massive evacuations and sending several people to local hospitals.

Essentia Health today said its Duluth and Superior hospitals treated a total of 16 victims related to the refinery incident, all but one were released. The one patient admitted was in good conditon Friday morning. St. Luke’s hospital in Duluth confirmed treating five refinery-related patients Thursday, all treated and released.

No fatalities were reported, and all employees and hundreds of contractors working at the refinery were accounted for.

No details were available on the extent of refinery damage or what caused the initial explosion that occurred just after 10 a.m., apparently in a tower near giant asphalt storage tanks. One of those tanks was punctured, spewing liquid asphalt onto the ground for hours.

A second, larger fire erupted just after noon with multiple explosions throughout the afternoon, sending a much bigger black cloud billowing for miles.

Kollin Schade, refinery manager for Husky, told reporters that the facility was preparing for a May shutdown for servicing and inspection at the time of the explosion and that most of the fire and smoke was from asphalt burning.

Firefighters stood by for several hours until it was clear that a potentially dangerous toxic chemical, hydrogen fluoride, was not at risk of exploding and then went “into offensive operations” with foam and water.

Superior Fire Battalion Chief Scott Gordon, shortly before 7 p.m. declared the fire to be out. Thursday evening a new fire ignited from a liquid Schade described as a “heavy material very similar to a bunker fuel that is not quite as heavy as asphalt but still very heavy,” which was pouring out of a valve that could not be shut off.

Gordon said the fire would continue to burn until all of the liquid burned off. It was unknown Thursday evening how much liquid was left or how long the fire would continue. Gordon said he is confident that the fire is isolated and will not spread or get bigger.

Evacuation

At a 3 p.m. press conference, Paine said everyone within a 3-mile radius of the refinery should evacuate and stay out. City and county officials also said that everyone who lived or worked within 10 miles south of the fire also should evacuate due to the potentially toxic nature of the spreading smoke plume.

“If in doubt … just leave. Find a place to go,” Paine said, later adding that “potentially all” of the city’s 27,000 residents may have to evacuate.

Though Paine had said he hoped most residents could be allowed to return by sunset Thursday, he announced at a news conference late in the evening that the evacuation remained in effect and would be re-evaluated throughout the night.

“We are hoping to lift that evacuation just as soon I feel satisfied and our team feels satisfied that the site is safe and that there is no further risk at the refinery or in the air surrounding the refinery, Superior and Duluth,” Paine said.

At 8 p.m. the city of Duluth issued a “shelter in place” advisory for the area including the Fond du Lac neighborhood east to the CN ore docks in West Duluth, and to the top of the hill, as winds were predicted to shift in that direction during the night. “Residents with health concerns are advised to close windows and doors and stay indoors overnight as residual smoke from the refinery fire in Superior could be a respiratory irritant if inhaled,” a statement from the city read.

Husky issued a news release saying that anyone affected by the fire could call 800-686-3192 for assistance with food, transportation or other concerns.

Essentia Health closed all of its Superior locations including evacuating everyone from its Superior hospital with all patients going to Duluth facilities. The University of Wisconsin-Superior evacuated and sent students to the College of St. Scholastica in Duluth.

Many of Superior’s main roads were clogged to gridlock with traffic through the afternoon as residents tried to move away from the smoke plume or retrieve loved ones who were evacuating.

Residents who evacuated and needed shelter gathered at the Duluth Entertainment Convention Center as the primary site.

Superior school officials said public school students in the city were evacuated to Amsoil headquarters in Superior where parents waited in traffic jams to pick up their children. Superior schools superintendent Janna Stevens said late Thursday afternoon that all students were either home safe with their families or were on their way home.

The Duluth Transit Authority sent buses to help move evacuees to safety.

UWS, all Superior public schools, Maple public schools and Wisconsin Indianhead Technical College all are closed Friday.

Many businesses also closed and evacuated, including Superior Water, Light and Power and the Superior Family YMCA, gas stations and some grocery stores.

The U.S. Coast Guard also imposed a closed safety zone near the Superior entry and Superior harbor due to the smoke dangers. It wasn't clear when that would be relaxed.

Hydrogen fluoride a concern

The Superior refinery is one of about 50 nationally that uses hydrogen fluoride to process high-octane gasoline. An acid catalyst, hydrogen fluoride is one of several federally regulated toxic chemicals at the refinery, such as propane and butane.

The refinery can handle about 78,000 pounds of hydrogen fluoride, according to federal Environmental Protection Agency records.

Schade, the refinery manager, would not answer specific questions on hydrogen fluoride Thursday, only saying its presence at the refinery was one reason the evacuation was underway.

A Superior Fire Department official said having the fire spread to the hydrogen fluoride tank would be the worst-case scenario for the situation to worsen, with other experts saying the fumes could spread a toxic cloud of gas for miles downwind.

Wisconsin Department of Natural Resources spokesman Jim Dick said the DNR had a spills coordinator on site, along with a team from the Environmental Protection Agency.



A 2011 report from the Center for Public Integrity called hydrogen fluoride an "extremely toxic" chemical that, if released into the atmosphere, can spread rapidly.

“It’s like chlorine gas. It’s an extremely toxic gas cloud that can move for miles downwind,” Fred Millar, a Washington, D.C.-based independent consultant and activist on refinery toxicity issues,

told the News Tribune. “If your local officials aren’t explaining how concerned they are about that, then they should be. It would be a disaster. That’s what the evacuation (distances) should be based on.”

Mayor says city was prepared

The mayor said city agencies and refinery crews have trained jointly for disasters at the facility, calling Thursday’s event “the nightmare scenario’’ for which they train.

“This community is aware we have an oil refinery. We’re prepared for this. We’ve done extensive training,” Paine said. “We’ve invested in equipment and infrastructure. We probably have the best fire department in the country to respond to an event like this.”

Mel Duvall, manager of media and issues for Calgary-based Husky Energy, said he had no information on where inside the refinery the initial explosion occurred. The company was planning a five-week turnaround starting in May, meaning parts or all of the plant would be shut down.

Officials at Enbridge Energy, which owns a massive oil pipeline terminal and storage facility with millions of gallons of petroleum products stored near the refinery, said their facility was not impacted.

“The Husky Terminal is across the street from Enbridge’s Superior Terminal. This incident has not impacted Enbridge’s Superior Terminal operations. Most Enbridge terminal employees have been evacuated except for a small crew who continue to monitor the situation,’’ said Jennifer Smith, an Enbridge spokeswoman. “Our thoughts and prayers are with the Husky employees and their families.”

Refinery had past violations

In 2015 the federal Occupational Safety and Health Administration fined former refinery owner Calumet $21,000 over emergency response and flammable-liquids violations. Those violations were marked as settled and the problems solved by the end of that year.

It was the only OSHA enforcement action taken against the refinery in the past 20 years, according to a search of the agency’s database.

In 2012 and 2013 there were four reports of hydrogen sulfide releases due to power outages, according to the National Response Center.

The refinery has not been fined over hazardous waste since 1999, according to the Environmental Protection Agency.

The refinery’s most recent Risk Management Plan was submitted to the EPA in 2012 and states: “In the unlikely event of a catastrophic release, the refinery, working in conjunction with local emergency management staff, is well prepared to respond and mitigate adverse consequences to the community or the environment.”

Husky took over in 2017

Husky Energy concluded its purchase of the refinery in November, spending $492 million to acquire the refinery from Calumet. The Canadian refiner said there were no changes planned for the facility, but it was planning to continue a $30 million upgrade started by Calumet.

About 180 people are employed at Wisconsin's sole refinery, which provides the Northland with gasoline, asphalt and other specialty petroleum products. About 50,000 barrels - or 2.3 million gallons - of oil per day can be processed at the refinery, located at 2407 Stinson Ave.

Along with the refinery, Husky took control of two asphalt terminals and two product terminals, a marine terminal, 3.6 million barrels in storage and a marketing business.

The Superior refinery was built in 1950, acquired by Murphy Oil in 1958 and sold to Indianapolis-based Calumet for $475 million in 2011.

Husky Energy said the Superior refinery had averaged 37,000 barrels per day of production in the first three months of this year, according to an earnings statement released Thursday morning.

News Tribune reporters Brooks Johnson, Jimmy Lovrien, Jana Hollingsworth, Peter Passi and Adelle Whitefoot, and Superior Telegram reporter Maria Lockwood, contributed to this story.