If you buy bread in Toronto, Paris, or Rio de Janeiro, it cannot by law contain the chemical potassium bromate. Yet if you eat baked goods in the U.S., you may be eating this substance unknowingly. Potassium bromate is used to whiten and strengthen dough, to reduce mixing time and enhance rising—but it was also classified by the World Health Organization (WHO) as a possible human carcinogen in 1999 after it was found to cause kidney and thyroid tumors in lab rats.

Declared unsuitable for use in flour by both the WHO and United Nation’s Food and Agricultural Organization in the early 1990s, potassium bromate—which can also cause non-carcinogenic adverse effects on the human kidney—is now banned in the European Union, China, and other countries around the world. It has also been listed as a carcinogen under California’s Proposition 65 since 1990.

But the U.S. Food & Drug Administration (FDA) continues to allow its use in flour. And according to a recent report from the Environmental Working Group (EWG), baked goods containing potassium bromate in the U.S. are widely available despite many companies’ shift away from the additive.

Used Despite a Ban on Carcinogenic Additives

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Why has potassium bromate stuck around? According to the FDA and the American Bakers Association, it has been used in flour in the U.S. since about 1915. The FDA first officially approved this use in 1941 and, despite the 1958 law known as the Delaney Clause, which bars carcinogenic additives and pesticide residues in food, the FDA has never withdrawn its approval for potassium bromate.

In 1999, the same year the WHO classified the additive as a carcinogen, the Center for Science in the Public Interest (CSPI) petitioned the FDA, asking it to ban the chemical from baked goods. More than 15 years later, the FDA has never responded definitively to the petition.

Instead, the FDA limits how much potassium bromate can be in flour and what levels of residues it considers acceptable in baked goods. But these limits don’t take into account cumulative exposure—or the fact that people might be exposed to by eating multiple servings of food made with bromated flour, explains Natural Resources Defense Council health and environment program director, Erik Olson.

EWG’s analysis suggests that many of the products that currently contain potassium bromate are produced by brands and bakeries catering to local, regional, and special ethnic markets—products to which people may be particularly loyal.

“That’s a concern because most people tend to purchase the same food over and over,” says Olson. For example, if your favorite Italian bread or Caribbean sweet rolls contain potassium bromate, that would mean than you might be getting more exposure than other people do. “There may be families that exclusively eat these small brands and they shouldn’t be any less protected than the rest of us,” says EWG report co-author and database analyst Jose Aguayo.

Brands to Watch

EWG’s analysis lists 86 products that include potassium bromate on their ingredient labels. And a search for potassium bromate as an ingredient turned up numerous additional products beyond those listed by EWG.

Among these are food items sold by Godfather’s Pizza, Papa Murphy’s, and regional brands such as La Rosa’s pizzerias in the Midwest, Philly Pretzel Factory, and Viga Italian Eatery in Boston. Others products that list potassium bromate as an ingredient include some sold under the Einstein Bagel’s brand name; a Papa Gino’s hamburger bun; and baked goods served by Valley Senior Services in Fargo, North Dakota.

The good news is that since CSPI filed its petition, most major brands have shifted away from potassium bromate. The organization’s executive director Michael Jacobson told Civil Eats, “The FDA has not acted on our petition, but the marketplace really has.”

Among the larger brands on EWG’s list, spokespeople from both Goya and Hormel told Civil Eats by email that they no longer use the additive. The same was true of a New York City bakery called Terranova, which Zagat’s has rated “extraordinary.”

But bromated flour remains on the market—sold by brands that include General Mills’ Pillsbury and All Trumps labels. An online search for these flours suggests that they may be most readily available on the East Coast, perhaps because of California’s Proposition 65, which requires products containing potassium bromate to carry a warning label.

There are also lots of bakery products sold at bakery counters and in restaurants. This means potassium bromate “may well be in products that aren’t purchased with ingredient labels,” says Tom Neltner, Environmental Defense Fund’s chemical policy director.

Should You Be Worried?

While the FDA limits the amount of potassium bromate in flour and bromate in baked goods, this is not the only potential source of bromate exposure. And a move away from potassium bromate doesn’t necessarily mean bread and other baked goods are free of worrisome chemical additives.

Some food companies—including Kroeger—now use a dough conditioning additive called azodicarbonamide, an industrial chemical that recently gained notoriety as it’s also used in plastics, in products that include flip-flops and yoga mats. While associated with increased incidence of tumors in female lab mice, the FDA says levels found in finished baked goods is not a concern. But azodicarbonamide is yet another chemical allowed in U.S. food, but banned in Europe and elsewhere.

Other sources of bromate exposure can include drinking water since bromate can be formed when ozone is used to disinfect water, explains NRDC’s Olson—a process used by many U.S. drinking water systems. This means that people may be exposed to multiple sources of bromate without knowing their cumulative exposure levels. And the FDA’s limit for bromate residues in baked goods—like the EPA’s limit for bromate in drinking water—is set without accounting for other sources.

The American Bakers Association maintains that the risk from exposure to potassium bromate from baked good is negligible. And CSPI’s Jacobson described the risk as “small,” given big brands’ move away from potassium bromide.

But EWG’s Aguayo and NRDC’s Olson still believe more regulation is needed. “Exposure is completely unnecessary since there are safer alternatives available,” says Aguayo. “Potassium bromate is just one example of the potential harms of our woefully outdated and inadequate food regulations.”

EWG has launched a petition asking food manufacturers to stop using potassium bromate. In the meantime, if you want to avoid bromated flour, read the fine print on food package labels and ask your local bakery or pizzeria to be sure—or choose organic.