The Department of Labor (DOL) sued three Alabama businesses, including a Hyundai Motor manufacturing plant, for employing a 13-year-old worker on an auto parts assembly line.

The lawsuit, filed Thursday in U.S. District Court for the Middle District of Alabama, asked the court to prevent Hyundai Motor Manufacturing Alabama, as well parts supplier SMART Alabama and staffing agency Best Practice Service, from benefitting from the use of child labor.

The DOL alleged a 13-year-old girl recruited by Best Practice Service worked up to 50-60 hours a week on an assembly line at SMART Alabama, which manufactured parts for Hyundai. The complaint alleged the girl worked for six to seven months on a section of the SMART Alabama assembly line that formed sheets of metal into body parts for cars.

All three companies jointly employed the child, the complaint alleged. The order asked the companies to disgorge all profits made from the use of child labor.

“Child labor is an unfortunate reality in the United States today. This case is about who bears responsibility for child labor violations in an automotive supply chain,” the lawsuit said.

“The Department of Labor’s complaint seeks to hold all three employers accountable in the supply chain,” Solicitor of Labor Seema Nanda said Thursday in a press release. “Companies cannot escape liability by blaming suppliers or staffing companies for child labor violations when they are in fact also employers themselves.”

In March, the DOL penalized Tennessee-based Tuff Torq Corp. $1.8 million for allowing a worker under age 18 to use a power-driven hoisting apparatus. The company claimed the employee was a temporary worker and not employed by the company. The penalty breakdown in that case was a $300,000 fine and $1.5 million in disgorgement.

In February, the DOL sought a nationwide restraining order against Fayette Janitorial Services, which cleans meat and poultry plants in about 30 states, in the wake of an investigation that the Tennessee-based company employed young children to clean a Perdue Farms plant in Virginia and a Seaboard Triumph Foods plant in Iowa.

Child labor in U.S. supply chains has become a more prevalent risk as thousands of underage migrant children have been found to work in the United States. As a result, the compliance community has been encouraged to be more thorough in conducting risk assessments for child labor in their U.S. supply chains, as the DOL has sought more authority to root instances of child labor and punish the companies benefitting from it.

In an emailed statement, a spokesperson for Hyundai said the use of child labor “is not consistent with the standards and values we hold ourselves to as a company.” Hyundai investigated the issue, took “extensive” remedial measures, and reported the results of its investigation to the DOL.

The company terminated its relationship with the third-party staffing agencies; implemented new, more stringent workforce standards throughout its supply chain; began requiring its Alabama suppliers to conduct independently verified audits; and introduced a new compliance training program for suppliers.

But the company said it objected to the way the DOL is handling the issue.

“Unfortunately, the Labor Department is seeking to apply an unprecedented legal theory that would unfairly hold Hyundai accountable for the actions of its suppliers and set a concerning precedent for other automotive companies and manufacturers,” the statement said. “We are reviewing the new lawsuit and intend to vigorously defend the company.”

SMART Alabama and Best Practice Service could not be reached for comment.