GRANITE CITY, Ill. (AP) -- Officials say an explosion at a southwestern Illinois steel plant has injured at least 10 people, three critically.
Fire officials say the blast happened shortly after 8 a.m. Thursday at American Steel in Granite City, just northeast of St. Louis.
A spokeswoman for the local hospital, Gateway Regional Medical Center, says at least 10 workers were treated there. Kate Allaria says seven of them inhaled smoke and are in "stable to guarded condition." Three others have been flown by helicopter to a St. Louis-area hospital with injuries she described as critical.
Assistant Fire Chief Jim Snelson tells the St. Louis Post-Dispatch it appears "some gas ignited."
Federal workplace safety officials are investigating. Calls to the business Thursday morning went unanswered.