Potassium Bromate Ban in the US: What It Means for Food Safety

On March 15, 2024, the California Department of Public Health enacted the state’s long-anticipated potassium bromate ban — making it illegal to sell food products containing the additive in the state of California. The move, enabled by the California Food Safety Act (AB 418, signed October 2023), sent shockwaves through the US baking industry and intensified a national conversation that had been simmering for years: why does the United States still permit a substance banned in the European Union, United Kingdom, Canada, Brazil, and more than 100 other countries as a food additive?

Potassium bromate (KBrO₃) has been used as a bread-improving agent in commercial baking since the early 20th century. It strengthens dough, improves texture, and allows bread to rise higher — properties that made it a staple additive for large-scale commercial bakers producing soft, uniform sandwich loaves. For decades, the FDA classified it as “generally recognized as safe” (GRAS). But the science shifted dramatically in the 1980s, and the regulatory response — at least in the United States — has been slow to follow.

The Science: Why Potassium Bromate Is Dangerous

Potassium bromate is classified as a Group 2B carcinogen (possibly carcinogenic to humans) by the International Agency for Research on Cancer (IARC), based primarily on animal studies showing that it causes renal cell tumors, thyroid tumors, and peritoneal mesotheliomas in rats when administered in drinking water. The key mechanism appears to be oxidative DNA damage — bromate generates reactive oxygen species that damage cellular DNA, a well-established pathway for carcinogenesis.

Proponents of potassium bromate’s continued use in baking have long argued that bromate reacts completely during the baking process, leaving no residue in the finished product. The FDA accepted this argument when reviewing the additive in the 1970s. But more sensitive analytical methods developed in the 1990s revealed that bromate residues do persist in commercially baked bread — at concentrations ranging from 0 to 100 parts per billion depending on baking time, temperature, and dough formulation.

A 1999 study in Food Additives and Contaminants tested 178 commercially purchased bread products in the UK and found measurable bromate residues in 18% of samples. A 2005 analysis of US commercial bread found similar residues. While the concentrations measured are typically well below the levels shown to cause cancer in animal studies, there is no established safe threshold for carcinogenic exposure — and cumulative lifetime exposure from daily bread consumption compounds over decades.

Children’s Elevated Risk

Children are of particular concern for bromate exposure for two reasons: they consume more food relative to body weight than adults, meaning a given concentration in bread represents a higher per-kilogram dose; and they have longer lifespans ahead of them over which cancer risk can accumulate. The Environmental Working Group (EWG), which has campaigned for a US federal ban, estimated in 2023 that potassium bromate exposure through bread and baked goods consumption is associated with approximately 60 additional cancer cases per 100,000 Americans — a risk level that would trigger regulatory action under most contemporary risk assessment frameworks.

The Regulatory History: A Tale of Two Systems

The divergence between US and international regulatory treatment of potassium bromate illustrates a fundamental difference in how the FDA and European food safety authorities approach the regulation of food additives. The EU operates under a precautionary principle framework: substances must be proven safe before approval, and approval is withdrawn when credible safety concerns emerge. The FDA historically operated under a different framework: approved substances remain permitted unless the agency takes active regulatory action to withdraw approval.

The EU banned potassium bromate as a food additive in 1990, following the IARC’s carcinogenicity assessment and the UK’s Committee on Mutagenicity’s conclusion that bromate was likely genotoxic. The United Kingdom issued its own ban in 1990. Brazil followed in 2001. Japan banned it in 2000. By 2020, more than 100 countries had prohibited it.

The FDA, by contrast, responded to the same science by asking the baking industry to voluntarily phase out potassium bromate use — a request issued in 1991 that was largely ignored. The agency acknowledged in a 1999 proposal that potassium bromate “may be a carcinogen” and initiated a rulemaking process to revoke its GRAS status. That rulemaking was never completed. The FDA continued to permit the additive for more than three decades after initiating what became one of regulatory history’s most protracted non-decisions.

The GRAS System: A Structural Problem

Understanding why the US was so slow to act requires understanding the GRAS (Generally Recognized as Safe) system, which allows food companies to self-certify that additives are safe without FDA approval — a system that the Government Accountability Office described in a 2010 report as having “weaknesses” that “do not provide assurance” of additive safety. Under GRAS, thousands of food additives are permitted based on industry-sponsored reviews rather than independent regulatory assessment.

Revoking a GRAS designation requires the FDA to affirmatively demonstrate that an additive is unsafe — a high evidentiary bar that requires significant agency resources and faces potential legal challenges from industry. The result is a system structurally resistant to de-listing additives even when credible safety concerns exist, which is precisely what happened with potassium bromate.

California’s Ban and the FDA’s 2024 Response

California’s action through the Food Safety Act created a new dynamic that finally generated federal momentum. When California — home to 39 million people and the largest US food market — bans an additive, food manufacturers face a practical choice: reformulate products for the California market specifically, or reformulate for the entire national market. For most large companies, maintaining separate product lines is operationally and economically impractical, meaning California’s ban effectively functions as a national ban for major brands.

This dynamic accelerated industry reformulation: major commercial bakers including Pepperidge Farm, Sara Lee, and many private-label suppliers announced they would eliminate potassium bromate from their products ahead of California’s enforcement timeline. With the industry reformulation already underway, the FDA finally announced in 2024 that it was reopening the rulemaking process to formally revoke potassium bromate’s authorization as a food additive — a process that, if completed, would result in a nationwide federal ban.

The FDA’s action aligns with its broader 2023 initiative to revisit several legacy GRAS designations using modern risk assessment methods. Potassium bromate was listed alongside brominated vegetable oil (banned in the US in 2023), propylparaben, and several synthetic colorings as substances under active review — the most comprehensive revision of authorized food additives in decades.

What It Means for Food Safety and Consumer Health

The practical significance of the potassium bromate ban for consumer health is real but contextually important to understand. The additive was already absent from most artisan, organic, and premium bread products — which tend to use longer fermentation processes that achieve similar dough-strengthening effects naturally. It was primarily present in high-volume commercial bread products, particularly inexpensive sandwich breads, dinner rolls, and flour tortillas.

For consumers of these products — disproportionately lower-income households for whom inexpensive commercial bread is a dietary staple — the ban removes a source of chronic low-level carcinogen exposure. The elimination of potassium bromate is unlikely to produce dramatic individual-level health benefits, since exposure levels were low; but at a population scale, removing a probable carcinogen from a food consumed daily by most Americans represents meaningful risk reduction.

Food manufacturers have not found the reformulation particularly challenging. Alternatives to potassium bromate — including ascorbic acid (vitamin C), azodicarbonamide (itself now under scrutiny), and enzyme-based dough conditioners — are widely available and effective. The fact that countries representing the majority of the world’s population have successfully banned potassium bromate without disrupting bread production or quality demonstrates that alternatives are technically viable.

The Broader Food Safety Context: Ultra-Processed Foods Under Scrutiny

The potassium bromate ban is part of a broader reexamination of food additive safety that is accelerating in the United States, driven by growing scientific consensus that the cumulative effects of the hundreds of additives in ultra-processed foods (UPFs) may be more significant than analysis of individual additives suggests. The UPF hypothesis, advanced most prominently by epidemiologist Kevin Hall and researchers at the NIH, posits that the combination of processing methods, emulsifiers, artificial colors, flavor enhancers, and chemical preservatives in ultra-processed diets — rather than any single additive — drives adverse health outcomes including obesity, metabolic syndrome, and certain cancers.

This perspective is influencing regulatory thinking at the FDA and within the HHS Make America Healthy Again initiative launched in 2025, which explicitly targeted ultra-processed food additives as a public health priority. The initiative included commitments to accelerate review of food dyes, emulsifiers, and preservatives — representing the most ambitious US food additive reform agenda in a generation.

International Harmonization: Closing the Gap

The potassium bromate situation — where a substance banned by virtually every other developed country was permitted in the world’s largest economy for decades — highlights the need for greater international harmonization of food additive standards. The Codex Alimentarius Commission, which establishes international food standards, does not authorize potassium bromate for use in bread, creating a situation where the US was formally out of step with internationally recognized food safety standards.

Consumer advocates argue that the US should adopt a stronger precautionary approach to food additive authorization — one that requires manufacturers to demonstrate safety before approval rather than requiring regulators to demonstrate harm after decades of use. This would align US food safety policy more closely with the EU’s approach and with the toxicological principle that burden of proof for safety should rest with those seeking to introduce a substance into the food supply, not with regulators seeking to remove it.

What Consumers Can Do Now

While federal regulatory processes play out, consumers can take practical steps to minimize potassium bromate exposure in states where it remains technically legal pending federal action:

• Check ingredient labels: potassium bromate must be listed on ingredient labels when present — look for “potassium bromate” or “bromated flour” in ingredient lists
• Choose organic bread products: the National Organic Program prohibits potassium bromate in certified organic products
• Seek artisan or whole grain bread: smaller-scale producers and whole grain producers rarely use potassium bromate, which is primarily used in highly refined commercial white bread production
• Use the EWG Food Scores database to check specific products for potassium bromate content
• Support federal rulemaking: submit comments to the FDA during public comment periods on the proposed revocation of potassium bromate’s authorization

Conclusion: A Ban Long Overdue

The potassium bromate ban — advancing in California and now triggering long-overdue federal action — represents both a food safety victory and a cautionary tale about the failures of regulatory inertia. A substance that international scientific consensus identified as a probable carcinogen in the 1980s continued to be used in American bread for four more decades, affecting the diets of millions of people who had no practical way to avoid it in mainstream commercial bread products.

The lesson for food safety policy is clear: voluntary industry phase-outs do not work when financial incentives point in the opposite direction; precautionary action is preferable to decades of inaction pending definitive proof of harm; and state-level action can be a powerful lever for forcing federal reform when federal agencies are gridlocked. California’s Food Safety Act has demonstrated that consumer protection legislation can overcome decades of regulatory stasis — and the result is safer bread for every American, wherever they shop.