A class-action federal lawsuit accuses 11 of the United States' largest beef and pork producers of conspiring to depress wages and benefits for its workers.

The lawsuit, filed in federal court in Denver on Friday, 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 was brought by two meat plant workers from Iowa and one from Georgia but seeks to represent hundreds of thousands of other people who have worked in jobs from slaughtering to production at the companies' collective 140 plants. Together the plants produce about 80% of the red meat sold to U.S. consumers, according to the lawsuit.