TAR HEEL, NC. – Fire department personnel and rescue workers were called to Smithfield Foods’ pork processing plant in Tar Heel at approximately 1 a.m. on Jan. 6, responding to reports of an ammonia leak. Company officials confirmed there was an overnight ammonia release in a refrigerated section of the plant, resulting in the company evacuating about 800 employees who were working at the time.

“Four employees were sent to the hospital for observation after experiencing nausea and have since been released,” said a Smithfield spokesperson.

All of the other workers were sent home and the company suspended operations on Jan. 6, while officials investigated the cause of the leak.

“We have identified the issue as a mechanical failure in a freezer,” the spokesperson said. “We are making repairs and expect to safely resume operations tomorrow.”

Smithfield’s Tar Heel plant is the company’s largest processing facility, employing approximately 5,000 workers.