LOUISVILLE, Ky. – A March 23 anhydrous ammonia leak resulted in the evacuation of 1,000 workers at the Louisville JBS Swift plant. The leak was contained to the plant. One plant worker who didn't work in the area where the leak occurred, went to the hospital after becoming ill. Fire officials asked persons within a quarter-mile area to stay indoors as they assessed the situation.

A call on the leak was first issued at 11:20 a.m., and sirens in Butchertown sounded more than an hour later, according to WLKY.com. Hazmat crews entered the building to find and stop the leak. Several hours later, workers were allowed to go inside and the plant started working its third shift.

Investigators believe a failed compressor caused the leak. An investigation into the leak is currently underway.