The U.S. Department of Labor (DOL) revealed on Friday that one of the country's largest food sanitation companies employed more than 100 children for dangerous jobs.

Packers Sanitation Services Inc. (PSSI), based in Kieler, Wisconsin, has paid $1.5 million in civil money penalties after a DOL investigation found that the company "employed at least 102 children - from 13 to 17 years of age - in hazardous occupations and had them working overnight shifts at 13 meat processing facilities in eight states," a statement read.

Children were working with hazardous chemicals and cleaning meat processing equipment including back saws, brisket saws, and head splitters, according to the investigation, which began in August 2022.

"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," Jessica Looma, principal deputy administrator of the DOL's Wage and Hour Division said. "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."

"Our investigation found Packers Sanitation Services' systems flagged some young workers as minors, but the company ignored the flags," Wage and Hour Regional Administrator Michael Lazzeri in Chicago said.

"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," Lazzeri added.

Forms of child labor, including indentured servitude and child slavery, have existed throughout American history, and the number of child laborers across the country peaked in the early decades of the 20th century, according to The University of Iowa Labor Center. Though the Fair Labor Standards Act was passed in 1938, it didn't ban child labor in the U.S.

Under U.S. labor law, children as young as 12 can work unlimited hours on farms of any size with parental permission, as long as they do not miss school. There is no minimum age for children to work on small farms or family farms.

The U.S. is the only country in the world that has not ratified the United Nations Convention on the Rights of the Child, a comprehensive human rights treaty on children's rights and notably the most widely ratified treaty since its introduction in 1989.