Investigators searched for the cause of the massive Thursday morning explosion at the refinery, capable of processing up to 38,000 barrels of oil a day, which shook the city of Superior, Wisconsin, home to about 27,000 people.
An explosion at a Wisconsin oil refinery chased residents from their homes on Thursday, and now, pollution experts say there were probably all kinds of toxins in the smoke that blew downwind.
People on the scene, including local journalists, were reporting hearing and feeling several explosions and seeing thick black smoke quickly emanating from the site.
Local press have reported that the initial blaze was put out by 11:20 am but after a series of follow-on blasts it took until 18:45 to declare the fires onsite fully extinguished. He said one Husky employee and one contractor had remained in the hospital overnight, but were likely going to be released today.
The chemical can permanently damage the eyes, skin, nose, throat, respiratory system and bones, according to a 2013 report issued by the United Steelworkers union, which represents many refinery workers.
The order to evacuate Thursday afternoon came as the fire became too hot to fight, causing crews to fall back and regroup.
Schools in Superior and nearby Maple, Wisconsin, are closed Friday as a precaution.
Paine emphasized that the evacuations are due to potential risks, saying there is no current threat to residents. Murphy sold it to Calumet Specialty Products in 2011 for $435 million, and Calumet sold it to Calgary-based Husky past year for $492 million.
At the time of the explosion, crews were in the process of shutting down the refinery so that repairs could be made to the decades-old facility, WDIO said.
"It felt like a truck hit the building", she said. It produces asphalt, gasoline, diesel and heavy fuel oils.
Husky Energy states all workers have been accounted for and that local air quality is being monitored. The Occupational and Health Administration fined Calumet US$21,000 for violations of emergency response and flammable liquids regulation.