DES MOINES, Iowa (AP) — A Tennessee-based sanitation company has agreed to pay more than half a million dollars after a federal investigation found it illegally hired at least two dozen children to clean dangerous meat processing facilities in Iowa and Virginia.

The U.S. Department of Labor announced Monday that Fayette Janitorial Service LLC entered into a consent judgment, in which the company agrees to nearly $650,000 in civil penalties and the court-ordered mandate that it no longer employs minors. The February filing indicated federal investigators believed at least four children had still been working at one Iowa slaughterhouse as of Dec. 12.

U.S. law prohibits companies from employing people younger than 18 to work in meat processing plants because of the hazards.

The Labor Department alleged that Fayette used 15 underage workers at a Perdue Farms plant in Accomac, Virginia, and at least nine at Seaboard Triumph Foods in Sioux City, Iowa. The work included sanitizing dangerous equipment like head splitters, jaw pullers and meat bandsaws in hazardous conditions where animals are killed and rendered.

One 14-year-old was severely injured while cleaning the drumstick packing line belt at the plant in Virginia, the investigation alleged.

Perdue Farms and Seaboard Triumph Foods said in February they terminated their contracts with Fayette.

The agreement stipulates that Fayette will hire a third-party consultant to monitor the company’s compliance with child labor laws for at least three years, as well as to facilitate trainings. The company must also establish a hotline for individuals to report concerns about child labor abuses.

A spokesperson for Fayette told The Associated Press in February that the company was cooperating with the investigation and has a “zero-tolerance policy for minor labor.”