TAR HEEL, NC – Officials with the North Carolina Department of Labor say its investigation of the June 17 ammonia leak at Smithfield Foods’ Tar Heel, NC pork plant may take up to six months to complete, according to a Fayetteville Observer report.

Neal O'Briant, a spokesman for the state’s Department of Labor, said the Occupational Safety and Health Division is investigating the incident, which is a standard procedure. “We will be interviewing employees and any other witnesses," he said. The Tar Heel plant processes about 32,000 hogs per day with a workforce of more than 4,800.

On the morning of June 17, the plant was forced to shut down while the day shift evacuated following an ammonia leak behind the plant, resulting in a loss of power and water. The Tar Heel pork-processing plant returned to full production on June 20.

Dennis Pittman, director of communications, previously told MEATPOULTRY.com that a holding tank for hot water "just came apart all at one time." Approximately 300,000 gallons of water spilled to the floor, and a valve on an ammonia reserve tank broke off leading to the evacuation of more than 2,000 workers. Transformers also were knocked over, Pittman added. The company brought in four generators to lower the temperature inside the plant until the power grid was restored.

More than 40 people at the plant were treated for symptoms of heat and ammonia inhalation, while 12 workers were taken to area hospitals. Most were treated at Cape Fear Valley Medical Center in Fayetteville and released.