Denver, Colorado (AP) A class-action federal lawsuit is accusing 11 of the United States’ largest beef and pork producers of conspiring to depress wages and benefits for its workers.

The lawsuit was filed in federal court in Denver last week. It alleges that the producers have worked together since at least 2014 to keep workers’ compensation lower than the market would allow in violation of the Sherman Antitrust Act.

It seeks to represent hundreds of thousands of other people who have worked in jobs from slaughtering to production at the companies’ collective 140 plants. The lawsuit says they produce about 80% of the red meat sold to U.S. consumers.