Tyson Foods Inc. has agreed to pay a $3.95 million civil penalty to settle alleged violations at facilities in four states, including Iowa, the U.S. Justice Department and Environmental Protection Agency announced today.

Eight separate accidental releases of anhydrous ammonia, used in refrigeration systems at Tyson plants, occurred between 2006 and 2012. One person died. Tyson has agreed to add safety measures in all of its Midwestern plants.  

Tyson has Iowa plants in Cherokee, Columbus Junction, Council Bluffs, Denison, Perry, Sioux City, Storm Lake and Waterloo. Tyson is based in Springdale, Ark.