Rating: Avoid

Purpose / Use

In the US, potassium bromate is approved for use as a dough strengthener, flour-treating agent, leavening agent, and oxidizing or reducing agent in food products.¹ It is used to increase bread volume and to produce bread with a fine crumb structure.

Products

Potassium bromate is used primarily in bread products including cookies, dough, noodles, and snacks. According to the USDA Branded Foods Database, potassium bromate is used in hundreds of foods sold in the US.

Safety assessment

Potassium bromate is banned for use in foods in many countries like the UK and Canada due to concerns it can cause cancer, with the notable exceptions of the US and Japan. In animal studies potassium bromate caused kidney and thyroid tumors in rats and kidney tumors in mice² and is considered a genotoxic carcinogen by the World Health Organization,³ meaning it causes cancer by damaging DNA. This is important because, even according to the FDA, genotoxic carcinogens can cause cancer at any exposure level, meaning there’s no dose that is entirely risk-free.⁴ On the basis of the cancer evidence in animal studies, the Joint Food and Agriculture Organization / World Health Organization Expert Committee on Food Additives (JECFA) in 1992 concluded that potassium bromate was not acceptable to use as a flour-treating agent.⁵ The International Agency for Research on Cacer (IARC) designated potassium bromate as “possibly carcinogenic to humans” in 1999 based on “sufficient evidence” that it caused cancer in rodents.²

While potassium bromate mostly breaks down during the baking process, bromate residues have been detected in bread made from bromated flour.³ In 1992-1993 and again in 1998-1999, the FDA tested dozens of baked goods and found bromate in many of them.⁶

In 1999, CSPI filed a petition to ban the use of potassium bromate in bread and other baked goods, but FDA never ruled on it.⁷ Instead, FDA reports that it worked directly with industry to “improve baking technology” to reduce the amount of bromate left in food when bakers use potassium bromate.⁸ However, the FDA is legally obligated to prohibit the use of cancer-causing additives in food. Relying on voluntary action from food companies is not sufficient to protect consumers nor is it legal. In March 2024, potassium bromate was added to the FDA’s List of Select Chemicals in the Food Supply Under FDA Review.⁸ More than two years later, the FDA has taken no regulatory action to protect consumers from this clearly unsafe additive.

In light of the cancer risks, CSPI rates potassium bromate as Avoid.

References

1. US Food and Drug Administration. Substances Added to Food (formerly EAFUS): POTASSIUM BROMATE. https://hfpappexternal.fda.gov/scripts/fdcc/index.cfm?set=FoodSubstances&id=POTASSIUMBROMATE
2. International Agency for Research on Cancer (IARC). Summaries & Evaluations: POTASSIUM BROMATE. 73 (1999); 481. Available: https://www.inchem.org/documents/iarc/vol73/73-17.html
3. World Health Organization. WHO Technical Report Series 859: Evaluation of Certain Food Additives and Contaminants. Forty-fourth report of the Joint FAO/WHO Expert Committee on Food Additives. Geneva 1995
4. 83 Fed. Reg. 50490. Food Additive Regulations; Synthetic Flavoring Agents and Adjuvants.
5. World Health Organization. Joint FAO/WHO Expert Committee on Food Additives. Potassium Bromate (WHO Food Additives Series 30). 1992. https://www.inchem.org/documents/jecfa/jecmono/v30je17.htm
6. Center for Science in the Public Interest. Consumer Group Calls for Ban On “Flour Improver” Potassium Bromate Termed a Cancer Threat. July 19, 1999. https://www.cspi.org/new/bromate.html
7. Center for Science in the Public Interest. Petition for Regulatory Action to Prohibit the Use of Potassium Bromate as a Food Ingredient in Bread and Other Baked Goods. July 19, 1999. https://www.regulations.gov/docket/FDA-1999-P-2418
8. US Food and Drug Administration. List of Select Chemicals in the Food Supply Under FDA Review. June 24, 2026. https://www.fda.gov/food/food-chemical-safety/list-select-chemicals-food-supply-under-fda-review#information

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