The change would extend the FDA's "threshold of regulation" (TOR) exemption, which currently allows potentially dangerous compounds to be used without review in food contact materials such as packaging or processing equipment, provided they are not carcinogenic and are present at levels below 0.5 parts per billion (ppb).
Under the new proposal, chemicals could also be used as ingredients added directly to food: as flavourings, preservatives, emulsifiers, processing aids, enzymes, stabilizers and binders, and for other purposes in ultra-processing.
The proposal was disclosed as part of a rule the FDA submitted to the Federal Register, the same month Robert F Kennedy Jr and the agency declared "promises kept" for closing the separate "generally regarded as safe" (GRAS) loophole, which had long allowed ingredients onto the market without review. Advocates say the TOR expansion, which was not mentioned in the public relations material, could undermine that claimed victory, and some have accused Kennedy of deception.
Critics argue the 0.5 ppb threshold is flawed because some chemicals, particularly hormone disruptors linked to brain damage and reproductive harm in children, are dangerous at far lower levels. They point to an existing TOR exemption that allowed the rocket fuel chemical perchlorate to be used in grain bags, dramatically increasing the amount of the compound found in children's cereal.
"The FDA and industry have this position that if there's only a little bit of something in the diet, then it's not going to be problematic, but that isn't supported by science of any kind," said Maricel Maffini, an independent food consultant who has worked on TOR issues.
"I don't know how they're going to square that circle because there are many ingredients that at very low levels also cause serious issues in the body," she added.
The FDA did not respond to a request for comment. Advocates described the proposal as a major win for big food, based on flawed science.