Mar-Jac Poultry has denied it knowingly hired minors for its Jasper, Alabama, plant, and also argued some workers were doing jobs that are not banned by federal rules.

Four minors as young as 16 were allegedly discovered working overnight at an Alabama slaughterhouse owned by the same firm that was found directly responsible for the death of a 16-year-old Mississippi worker last summer, the U.S. Labor Department said in federal court filings.

The company, Mar-Jac Poultry, has denied that it knowingly hired minors for its Jasper, Alabama, facility, saying the workers had verified IDs that gave ages older than 17, and has also argued that some of the workers were performing jobs that are not prohibited by federal regulations.

The Labor Department is seeking a temporary restraining order against Mar-Jac as part of the ongoing legal dispute. Agency officials declined to comment, citing their investigation.

The Labor Department has said that most slaughterhouse work is too dangerous for minors and is prohibited by federal regulations. Under the Biden administration, the department has taken action against companies for employing minors to clean, use or work near dangerous machinery. A chicken trade group to which Mar-Jac belongs says it has “zero tolerance” for employing minors, and a major meat industry trade group also stated recently that no minors should be working in slaughterhouses.