At Least 11 Hurt in Explosion at Wisconsin Refinery

A tank containing crude oil or asphalt exploded at a large refinery in Wisconsin on Thursday, injuring 11 people and causing a blast that one worker described as sounding like a sonic boom.

Essentia Health spokeswoman Maureen Talarico says five patients are being treated at St. Mary's Medical Center in Duluth, Minnesota. She says emergency room physicians describe those patients as awake and alert.

Talarico says another five are being treated at St. Mary's Hospital in Superior, Wisconsin, where the explosion happened. She says the extent of injuries is unknown.

In Duluth, spokeswoman Jessica Stauber says St. Luke's Hospital is treating one person. She doesn't know the condition of that person.

The explosion at the Husky Energy oil refinery happened Thursday morning. Superior Fire Chief Steve Panger has said there are no known fatalities.

Panger earlier said the fire was out, but Superior police tweeted that the fire has reignited but that there is no need for residents to evacuate.

A contractor who was inside the building told WDIO television that the explosion sounded like "a sonic boom" and that it happened when crews were working on shutting the plant down for repairs.

Panger said the fire was out by 11:20 a.m., although smoke could be seen rising from the plant. Panger said a small tank exploded containing either crude oil or asphalt.

Superior police are advising people to stay away from the area and roads around the refinery have been blocked off. There have been no neighborhood evacuations. Superior is a city of about 27,000 people that borders Minnesota to the north and the tip of Lake Superior.

No damage estimate was available. The Superior Fire Department sent all three engine companies to the explosion, and nearby Duluth sent over a command vehicle.

Calgary-Alberta-based Husky Energy refinery bought the refinery from Indianapolis-based Calumet Specialty Products Partners last year for over $490 million. It's Wisconsin's only refinery, and it produces gasoline, asphalt and other products.

The refinery, which dates back to the early 1950s, has a processing capacity of around 50,000 barrels per day and a storage capacity of 3.6 million barrels of crude and products. It processes both heavy crude from the Canadian tar sands in Alberta and lighter North Dakota Bakken crude.