A vegan is suing Burger King over its Impossible Whopper , which is made by plant-based Impossible Burgers but cooked on the same grills as traditional beef Whoppers, rendering them unfit—according to the suit—for people who don’t eat animal by-products.

The lawsuit, filed by Phillip Williams in the U.S. District Court for the Southern District of Florida, was entered on the docket today. He wants it to be a class-action suit.

Court documents describe Impossible Whoppers cooked on the regular grills as “contaminated” and say vegans who know this is how they’re prepared wouldn’t buy them.

Williams calls Burger King‘s business practices false and misleading and accuses the fast-food chain of violating Florida’s Deceptive and Unfair Trade Practices Act, breach of contract, and unjust enrichment.

Williams bought an Impossible Whopper without mayonnaise (problematic for a vegan, with eggs among the condiment’s ingredients) from a Burger King drive-thru in Atlanta because he saw no signs saying it was cooked on the same grill as an animal-based Whopper. When Williams got his order, he checked that it was mayo-free and then ate the Impossible Whopper.

“Plaintiff, like the other members of the Class, reasonably believed that the Impossible Whopper was in fact ‘0% beef’ and, therefore, did not contain any meat or meat by-products. Plaintiff would not have purchased the Impossible Whopper if he knew that it . . . was coated in meat by-products,” according to court documents.

The suit accuses Burger King of violating vegans’ rights through its unfair and deceptive practices and wants the chain to “return all benefits gained, profits received, etc. from its deceptive marketing and sale of its Impossible Whopper so as to make full restitution to Plaintiff and the Class” and make an actual meat-free Impossible Whopper. It also asks for injunctive and equitable relief and actual, compensatory, and any other damages the court sees fit to award. No dollar amounts are listed in the suit.

“We do not comment on pending litigation,” Burger King said in an email to Fast Company.