The Labor Department said Friday that a Wisconsin-based company that provides workers to sanitize food processing plants paid a $1.5 million fine for illegally employing 102 children to clean meatpacking plants on overnight shifts in eight states.

The company, Packers Sanitation Services, allegedly employed minors as young as 13 to use dangerous chemicals to clean "back saws, brisket saws and head splitters." Investigators learned of at least three minors who suffered injuries while working for the company.

"The child labor violations in this case were systemic and reached across eight states, and clearly indicate a corporate-wide failure by Packers Sanitation Services at all levels," said Jessica Looman, principal deputy administrator of the Labor Department's wage and hour division, in a statement. "These children should never have been employed in meat packing plants and this can only happen when employers do not take responsibility to prevent child labor violations from occurring in the first place."

The plants are operated by some of the country's most powerful meat and poultry producers, including Tyson, JBS Foods and Cargill. Those companies were not implicated in the malpractice.

The $1.5 million fine amount is dictated by the Fair Labor Standards Act, which allows a penalty of $15,138 for each minor who was employed in violation of the law, according to the Labor Department.

In a statement, the company said, "We are pleased to have finalized this settlement figure as part of our previously announced December resolution with the Department of Labor (DOL) that ends their inquiry. We have been crystal clear from the start: Our company has a zero-tolerance policy against employing anyone under the age of 18 and fully shares the DOL's objective of ensuring full compliance at all locations."

"As soon as we became aware of the DOL's allegations, we conducted multiple additional audits of our employee base. ... Our audits and DOL's investigation confirmed that none of the individuals DOL cited as under the age of 18 work for the company today, and many had separated from employment with PSSI multiple years ago."

Packers Sanitation Services employs 17,000 workers at 700 sites nationwide.

"Our investigation found Packers Sanitation Services' systems flagged some young workers as minors, but the company ignored the flags. When the Wage and Hour Division arrived with warrants, the adults — who had recruited, hired and supervised these children — tried to derail our efforts to investigate their employment practices," said Michael Lazzeri, regional administrator for the Wage and Hour division in Chicago.

The DOL investigation started in August after the agency received a referral from local law enforcement in Nebraska about possible child labor violations at the Grand Island plant.

In January, three officials from the Department of Homeland Security told NBC News that federal investigators were looking into whether any of the children were victims of labor trafficking.

As of now, there is no indication DHS is currently investigating Packers for human trafficking.