Authorities say an ammonia leak at a poultry processing plant on Saturday morning (20 June) killed one person and injured four others, reports Fayetteville Observer.

The leak happened about 10:00 at the Mountaire Farms plant on N.C. 71, about 16 miles south of Fayetteville. Authorities said they do not know what caused the leak.

Robeson County Sheriff, Kenneth Sealey, identified the worker who died as Clifton Swain of Fayetteville. It was not known how he died. His wife declined to comment.

Between 30 and 40 employees were in the plant when the leak occurred, said Mike Tirrell, the vice president of processing operations for Mountaire Farms.

Charles Britt, Robeson County's Emergency Services director and fire marshal, said there was neither an explosion nor a fire.

Ammonia is the primary refrigerant in facilities that process meat products. It can cause burns when it is released, he said. The leak had been contained by Saturday afternoon but crews remained at the plant taking readings to make sure, he said.

Officials with Mountaire Farms released a statement expressing their condolences for the victims and their families.

"We are deeply grateful for the work of the emergency and public safety officials during this crisis," the statement said. "We will provide whatever resources are necessary to assist local and state authorities in their investigation."

Mountaire Farms bought the Lumber Bridge plant from Piedmont Poultry in 1996 and doubled production at the facility three years later, according to the company's Web site. There are 2,500 employees at the Lumber Bridge plant, Mr Tirrell told Fayetteville Observer.