Some workers at the Tyson Foods pork plant in Waterloo, IA were evacuated during a “minor” ammonia leak Friday afternoon, the company told several local news organizations.

Evacuations were ordered for part of the facility as a precaution, the company said in coverage by KWWL. The plant uses ammonia in its refrigeration system.

The evacuated “hit side” section of the plant was operational by Friday afternoon, Tyson stated in an account by the Waterloo-Cedar Falls Courier. No injuries occurred during the incident.

Several other ammonia leaks have occurred at Tyson facilities in recent years. Two contractors were injured during an ammonia leak at the Tyson Prepared Foods plant in Hutchinson, KS in November 2020. A HAZMAT team was dispatched to Tyson’s chicken processing plant in Noel, MO in February 2021 for an ammonia leak.