Wisconsin oil refinery fire out, at least 15 hurt: officials

By Stephanie Kelly and Erwin Seba

NEW YORK/HOUSTON (Reuters) - An explosion at Husky Energy's refinery in Superior, Wisconsin, caused a fire that burned for several hours on Thursday and sent smoke billowing into the air, prompting the evacuation of thousands of residents, officials said.

Local media said at least 15 people were injured but no fatalities were reported. All of the refinery's workers were accounted for, Husky said.

After flames were extinguished, an evacuation order remained in effect as officials verify the area is safe, Superior Mayor Jim Paine told a news conference. "This was the nightmare scenario" for the city of 27,000 people, he said.

At least 10 people were taken to area hospitals, one of whom was seriously injured, said a spokeswoman for Essentia Health-St. Mary's Medical Center, which operates hospitals in Superior and nearby Duluth, Minnesota.

After an initial blaze, a storage tank was punctured, and a second fire erupted, Husky Energy spokesman Mel Duvall said.

Firefighters tried to prevent flames from spreading by spraying water on nearby tanks, manager Kollin Schade said at a briefing.

The refinery, which can process up to 38,000 barrels of oil a day, had additional workers on site preparing for a plant-wide overhaul, he said.

The U.S. Chemical Safety and Hazard Investigation Board has sent a four-person team to investigate. The non-regulatory federal agency investigates serious chemical accidents such as refinery fires.

As a precautionary measure, local officials ordered all residents within a three-mile radius around the refinery to evacuate. Friday classes were canceled in Superior and nearby Maple school districts, also as a precaution, officials said.

"The lights flickered three times and the whole building shook," said Jim Ronning, owner of Hudy's Tavern in Superior, located about a mile from the facility.

"You can still smell a real caustic smell in the air," said Sara Haugen, owner of Pudge's bar in Superior, located about 135 miles from Minneapolis, Minnesota. "There's a big black plume of smoke coming out.

Husky purchased the refinery from Calumet Specialty Products Partners LP last year, saying at the time that it intended to keep all of its workforce of 180. It produces asphalt, gasoline, diesel and heavy fuel oils, largely using heavy crude oil imported from Canada.

Husky shares fell 8 percent to C$17.54 on the Toronto Stock Exchange, the same day it reported financial results.

(Reporting by Vijaykumar Vedala and Arpan Varghese in Bengaluru, Stephanie Kelly in New York, Liz Hampton and Erwin Seba in Houston and Jon Herskovitz in Austin; Editing by Chizu Nomiyama, Scott Malone and Cynthia Osterman)