Hospital: 3 critically hurt in blast at Ill. plant

Hospital: At least 10 hurt, 3 critically, in explosion at steel foundry in southwest Illinois

This image from video provided by KMOV-TV in St. Louis shows an injured worker is helped into a helicopter outside the American Steel plant in Granite City, Ill., Thursday, March 7, 2013, where an explosion injured at least 10 people, three critically. (AP Photo/Courtesy KMOV-TV in St. Louis) TELEVISION OUT

ST. LOUIS (AP) -- At least two people are hospitalized in critical condition after an explosion at a manufacturing plant in southwestern Illinois.

Authorities say 10 people were taken to hospitals after the explosion Thursday at the American Steel Foundries plant in Granite City, just northeast of St. Louis.

Gateway Regional Medical Center spokeswoman Kate Allaria says seven workers were treated for smoke inhalation and have been released. She says three workers were flown to nearby Missouri hospitals.

A spokeswoman at one of those hospitals says the two victims it received were in critical condition. The whereabouts of the other worker wasn't immediately clear.

Granite City Assistant Fire Chief Jim Snelson told the St. Louis Post-Dispatch gas somehow caught fire near a grinding machine at the plant that makes railcar components, causing an explosion.