Source: Chris Scott, MEATINGPLACE, 8/29/11

Investigators are still trying to determine the cause of an ammonia leak at a Pilgrim’s Pride poultry facility in Union County, N.C., even as employees return to work at the damaged plant.

The Greeley, Colo.-based company confirmed reports that all 550 employees returned to work this morning less than two weeks after the leak of anhydrous ammonia cleared the facility and also forced the evacuation of some nearby residents as a precaution.

The initial incident is believed to have been caused by some sort of explosion that damaged part of the plant but the investigation continues, according to local officials.

Some of the affected workers reportedly returned to work Sunday night and all shifts at the poultry plant were back in operation as of this morning.

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