An explosion at an oil refinery of Calgary-based Husky Energy has injured at least 11 people in the state of Wisconsin, USA, and forced the evacuation of homes, schools and a hospital. more than sending a cloud of toxic smoke into the atmosphere, according to the authorities.
Residents of the city of Superior, where the incident occurred, were allowed to return home Thursday night after a forced evacuation earlier in the day.
The fire, which sent a thick cloud of harmful black smoke into the air, was extinguished around 6:45 pm, said Husky Energy in a statement.
Authorities said a tank of crude oil or asphalt exploded at around 10 am at the refinery in Superior, a town of around 27,000.
The authorities said that a person was seriously injured at the time of the explosion, but no one died. They add that the black smoke sent into the atmosphere is toxic and require residents to take precautions.
An evacuation order was given after the explosion within a radius of 5 kilometers around the refinery, which is in an industrial zone, but where there is also a residential area nearby.
The schools of Superior canceled their classes on Friday as a precaution.
Husky Energy of Calgary, Alberta, purchased the Calumet Specialty Products Partners refinery in Indianapolis last year for $490 million. It is the only refinery in Wisconsin and produces gasoline, asphalt and other products.