KANSAS CITY, MO. — An Ammonia leak at the Farmland Foods plant the afternoon of Dec. 22 resulted in the evacuation of the company’s workers. According to KMBC.com, four people were taken to the hospital to be treated for respiratory problems. A faulty valve was initially thought to be the cause of the leak, and emergency crews were working to find the source and fix it.

A stretch of highway near the plant was closed as a precaution. Farmland Foods is a subsidiary of Smithfield Foods, Smithfield, Va.