Tyson Foods has agreed to pay a nearly four million dollars to settle alleged violations of Clean Air Act regulations at its facilities in Iowa, Kansas, Missouri and Nebraska, the Justice Department and Environmental Protection Agency announced today.

As part of a consent decree lodged Friday in U.S. District Court in St. Louis, Mo., Tyson has agreed to conduct testing and audits to improve compliance at all 23 of the company’s facilities in the four Midwestern states.

Those facilities include Tyson operations in Cherokee, Columbus Junction, Council Bluffs, Denison, Perry, Sioux City, Storm Lake and Waterloo in Iowa; Emporia, Finney County, Olathe, South Hutchinson and Hutchinson in Kansas; Concordia, Dexter, Monett, Montgomery City, Noel and Sedalia in Missouri; and Dakota City, Lexington, Madison and Omaha in Nebraska.

The company agreed to pay a civil penalty of $3,950,000 to settle allegations that stem from a series of eight separate incidents between 2006 and 2010. Officials say accidental releases of anhydrous ammonia at Tyson facilities resulted in property damage, multiple injuries, and one fatality.