Two of the most popular fast-food chains in the world are facing lawsuits for using PFAS (per-and polyfluoroalkyl substances, aka "forever chemicals") in their packaging.

Many restaurant chains have vowed to eliminate their use of PFAS over time, especially after the United States Environmental Protection Agency (EPA) announced an initiative to restrict their use last year. But it’s apparently not soon enough for some consumers.

Following recent report from Consumer Reports that found significant levels of PFAS in several McDonald’s and Burger King packaging, three lawsuits were filed against the two chains, reported National Restaurant News (NRN).

After testing over 100 food packaging products from 24 restaurant and grocery chains, Consumer Reports found PFAS in multiple types of packaging from every retailer in their research — including chains that promote healthier food, such as Cava and Sweetgreen.

At McDonald’s, the highest levels of chemicals were discovered in the bags for fries, cookies and Chicken McNuggets and the Big Mac container. Meanwhile, Burger King’s cookie and French toast sticks bags, Whopper wrapper and chicken nuggets bags had higher levels of PFAS than other packaging. Consumer Reports also noted that a McDonald's Big Mac container that used paper from "responsible sources" included PFAS.

Of course, the two burger chains were hardly alone in their use of packaging containing the toxic compound. Taco Bell, Chick-fil-A, Arby's, Trader Joe's and Stop & Shop also had high levels of PFAS in some of their packaging products, according to the report. Other companies with lower levels included Chipotle, Panera Bread, White Castle and Whole Foods.

Despite the exhaustive list of retailers involved in the research, so far, the lawsuits that have been filed since the release of Consumer Reports' research have only been against McDonald's and Burger King.

At least three lawsuits have been filed so far

A lawsuit filed in the U.S. District Court for the Southern District of Illinois on March 28 alleges that McDonald’s has exposed consumers to high levels of PFAS that have a “host of health effects,” NRN reported. The plaintiff also claims that the restaurant violated its food-safety pledge by using harmful chemicals.

A California resident also filed a similar lawsuit against the Chicago-based company on March 30 in the U.S. District Court for the Northern District of Illinois.

Earlier this month, a separate plaintiff sued Burger King in the U.S. District Court for the Northern District of California, calling out the restaurant's claim that it uses sustainable packaging and "real ingredients" with "no secrets" in the complaint.

The plaintiffs are seeking class-action status, and the lawsuits are mostly focused on claims of false advertising.

“The use of PFAS in its Products stands in stark contrast to McDonald’s brand identity which espouses food safety,” one suit reads, according to Top Class Actions. “In almost every medium, McDonald’s Corporation tells consumers, investors, and the general public that the Products are safe.”

When reached for comment, a Burger King spokesperson told TODAY Food, "Burger King does not comment on pending or potential litigations. However, Burger King has previously committed to eliminating PFAS from all guest packaging by 2025 (or sooner)."

Meanwhile, McDonald's issued the following statement to TODAY:

“McDonald’s stands behind its commitment to the safety of its food and food packaging. We removed a significant subset of PFAS, including Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), from all guest packaging globally in 2008. Our focus continues to be on furthering our product stewardship journey, including actions on our commitment to ensure all added fluorinated compounds are eliminated from our guest packaging materials globally by 2025. We disagree with the plaintiffs’ allegations, and will continue to defend against the baseless claims made in these complaints.”

Last month, Restaurant Brands International said, like McDonald's and Burger King, it would be banning PFAS in food packaging globally by 2025. Consumers are clearly eager for the companies to act quickly, but global supply chain shortages could potentially make that difficult.

 This article originally appeared on Today.com