Explosion rocks Wisconsin refinery, at least 5 hurt

An explosion rocked a large refinery in Wisconsin today, injuring several people, a fire official said.

The blast at the Husky Energy oil refinery happened at about 10 a.m. Five people were taken to hospitals in Duluth, Minnesota, Superior Fire Chief Steve Panger told The Associated Press. He doesn't know the extent of their injuries. Others were walking wounded. There were no known fatalities.

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 am. He said a small tank exploded, and the product was 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 neighbourhood 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 produces gasoline, asphalt and other products.

The refinery, which dates back to the early 1950s, has a professing 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.