A fire chief says four employees have been hurt in a chemical explosion at the General Motors Corp. metal-stamping plant in Marion, Indiana.

Marion Fire Department Assistant Chief Greg Yeakle says one of the workers has been rushed to Marion General Hospital in critical condition.

The Marion Chronicle-Tribune reports two employees were hosed down at the scene by firefighters and then taken away by ambulance. Another employee was washed down in a shower.

Yeakle says investigators believe chlorine and bromide were involved in the explosion.

The plant about 45 miles southwest of Fort Wayne was evacuated.

GM issued a statement saying a small explosion occurred and emergency responders had the situation under control. It says three employees were taken to the hospital and others were treated on site.