California lawmakers recently voted to prohibit “forever chemicals” in cookware and various other products, a decision that has not pleased everyone. A collection of well-known chefs—some of whom market or endorse nonstick pots and pans containing chemicals covered by this new ban—are seeking to prevent its implementation.

The freshly enacted legislation targets per- and polyfluoroalkyl substances (PFAS)—colloquially known as “forever chemicals”—in categories including cookware, cleaning supplies, dental floss, ski wax, food packaging, and specific children’s items. The California legislature overwhelmingly approved the bill, which will now proceed to the Governor’s desk. 

These synthetic chemicals earn their “forever” designation because they represent one of the most persistent classes of chemicals ever created, explains Scott Belcher, a professor of environmental toxicology and director of North Carolina State’s Oceans and Human Health Center.

“[PFAS] are highly fluorinated, purely synthetic chemicals, and have a chemistry that had never existed on the planet until towards the end of World War II. That is partially why they’re so difficult to break down and so challenging to remove,” Belcher conveyed to TIME. He added, “They’re really in absolutely everything globally at this point.”

Belcher, who has conducted extensive research on PFAS, states that the California legislation constitutes “much-needed regulation” and aligns with other efforts to phase out and outlaw these chemicals.

Yet, a contingent of celebrated chefs, some of whom promote their own cookware lines, aims to obstruct the new law. Rachael Ray, David Chang of Momofuku in New York City, and Thomas Keller from Napa Valley, California’s renowned French Laundry restaurant, each dispatched letters to the legislature, urging a reconsideration of the law due to its inclusion of a ban on polytetrafluoroethylene (PTFE), the substance responsible for making cookware nonstick.

“I respect and share the desire to protect Californians and our planet, but I urge you to look closely at the science before moving forward with legislation that could unintentionally do more harm than good. PTFEs, when manufactured and used responsibly, are proven to be safe and effective,” one letter stated.  

The chefs’ statements were compiled and distributed by The Cookware Sustainability Alliance, an entity established by two of the world’s largest cookware manufacturers, Groupe SEB and Meyer. The group’s website asserts that the ban would lead to increased cookware costs and labels the new law “a misguided proposal that would ban essential, safe, FDA-approved nonstick cookware made with the same compounds found in life-saving medical devices, such as pacemakers.” Furthermore, many of the letters contend that the Food and Drug Administration (FDA) authorizes PTFE and other fluoropolymers for food-contact applications.

Ray has her own line of cookware, while Chang offers nonstick frying pans and woks in collaboration with the manufacturing company Meyer. Keller also has his cookware produced by Hestan.

Critics of the chemicals argue that the materials used to confer nonstick properties to pans can still become toxic when heated to high temperatures, and that non-stick-coated cookware can also release harmful substances to consumers. 

“It’s actually the components that are leaching out of the polymer that are used in the manufacturing process,” Belcher explains, pointing out that byproducts from the manufacturing can contaminate the environment.

The chefs have also faced online backlash from environmental activists, including actor Mark Ruffalo, who specifically called out Ray on X for her opposition to the bill.

“Rachel, I share your commitment to making people confident in the kitchen,” Ruffalo posted. “Getting toxic chemicals like PFAS out of your cookware is just as important as choosing the right recipe.”

Public health officials have been increasingly sounding the alarm about forever chemicals in recent years. These chemicals exist in 12,000 different forms and are utilized to make cookware non-stick, to render clothes and carpets more stain resistant, to enable food packaging to repel grease, among other applications. According to available data, nearly all Americans have detectable levels of PFAS in their blood.

The Environmental Protection Agency (EPA) reports that PFAS toxicology has been linked to decreased fertility, high blood pressure in pregnant individuals, developmental delays in children, an elevated risk of certain cancers, hormone disruption, and diminished vaccine response. Still, the CDC indicates that since 2002, the use of PFAS in the U.S. has declined, leading to a corresponding reduction in some blood PFAS levels.