DES MOINES, Iowa (AP) — U.S. authorities have accused a sanitation company of illegally hiring at least two dozen children to clean dangerous meat processing facilities, the latest example of illegal child labor that officials say is increasingly common.

The Labor Department asked a federal judge for an injunction to halt the employment of minors by Tennessee-based Fayette Janitorial Service LLC, saying it believes at least four children were still working at one Iowa slaughterhouse as of Dec. 12.

U.S. law prohibits companies from employing people younger than 18 to work in meat processing plants because of the hazards involved. The Labor Department alleges that Fayette has used underage workers in hazardous conditions where animals are killed and rendered. The agency says children sanitize dangerous equipment, including head splitters, jaw pullers and meat bandsaws.

The department’s legal filing details the severe injuries one 14-year-old sustained while cleaning the drumstick packing line belt at a plant in Virginia. Records show Fayette learned the worker was underage after the child was injured and continued to employ the minor anyway, according to an investigator.

A spokesperson for Fayette told the Associated Press in an email that the company is fully cooperating with the investigation, and has made changes to policies to improve its hiring. That includes hiring a new CEO and using third-party legal representation for vetting, according to the company.

“Fayette has always had a zero-tolerance policy for minor labor in the workforce, and we have continued to work diligently to ensure that something like this cannot occur,” the statement said.

The latest findings add to a growing list of violations, including the fatal mangling of a 16-year-old working at a Mississippi poultry plant, the death of a 16-year-old after an accident at a sawmill in Wisconsin, and last year’s report of more than 100 children illegally employed by Packers Sanitation Services Inc., or PSSI, across 13 meatpacking plants. PSSI paid over $1.5 million in civil penalties.

Agriculture Secretary Tom Vilsack sent a letter to the 18 largest meat and poultry producers last year to highlight the issue as part of the administration’s effort to crack down on child labor violations more broadly. The Labor Department’s latest statistics indicate the number of children being employed illegally in the U.S. has increased 88% since 2019.

The cleaning company works in about 30 states and employs more than 600 workers, according to the department, and the investigation is ongoing. The initial findings identified 15 underage Fayette employees at a Perdue Farms plant in Accomac, Virginia, and at least nine at Seaboard Triumph Foods in Sioux City, Iowa.

Seaboard Triumph Foods said in a statement it is terminating its contract with Fayette because of the allegations. A spokesperson for Perdue Farms said in an email that the company terminated its contract with Fayette before the filing but declined to specify further.