Chicago (AFP) – Several people were injured and an expansive area evacuated Thursday after an explosion and fire at an oil refinery in the Midwestern US state of Wisconsin. 

Residents were ordered evacuated within a wide area in Superior, a city with a population of 27,000 near the northern tip of the state and less than 200 miles (320 km) from the Canadian border. 

An initial explosion occurred around 10:06 am (1506 GMT) at the Husky Energy oil refinery. It was followed by multiple subsequent explosions and a spreading fire that appeared to burn out of control inside the refinery complex — spewing thick black smoke high up into the sky.

“There are injuries, which are being treated at hospital and on site,” Husky energy said in a statement. The extent of those injuries were unclear. 

The Superior fire department said five people were “transported” from the scene. No fatalities were reported. 

The smoke prompted officials to order evacuations within a two to three-mile radius of the refinery and extending 10 miles to the south. Area schools were closed and students moved to other locations. 

“I’m told that this fire will likely burn until the fuel is consumed. And that could be a couple of days,” Superior police chief Nicholas Alexander told television station WDIO.

Cheryl Thielman, 58, who manages a mobile home park near the refinery, told AFP that the first explosion was a “huge boom.”

“It shook the trailer park,” she said, at the time suspecting that “maybe a train had possibly derailed” at the nearby railroad tracks. 

John Anderson, an employee of Stadium Towing, which had workers near the site of the explosion, told AFP that emergency crews were clearing the scene. 

A caravan of cars could be seen leaving the area. 

The refinery, which Husky Energy purchased last year, processes crude oil from Canadian and North Dakota fields. 

About 180 people are employed at the refinery, where about 2.3 million gallons of oil are processed per day, according to the Duluth News Tribune.