MINNEAPOLIS >> One of the country’s largest cleaning services for food processing companies employed more than 100 children in dangerous jobs at 13 meatpacking plants across the country, the U.S. Department of Labor said Friday as it announced over $1.5 million in civil penalties.

The investigation into Packers Sanitation Services Inc., or PSSI, began last summer. Department officials searched three meatpacking plants owned by JBS USA and Turkey Valley Farms in Nebraska and Minnesota, and found 31 underage workers as young as 13. They also searched PSSI’s headquarters in Kieler, Wisconsin. Underage workers were found at plants in eight states.

The department went on to review records for 55 locations where PSSI provided cleaning services and found even more violations, involving children ages 13-17.

The agency obtained a temporary restraining order in November and a permanent injunction in December, when PSSI entered into a consent judgment that committed the company to no longer employ minors illegally.

Over the past three years, children were found to be using caustic cleaning chemicals and cleaning “dangerous power-driven equipment, like skull-splitters and razor-sharp bone saws,” an official said.