Potassium bromate in food: ingestion safety
Moderate riskDietary ingestion via bromated flour bread products is the only meaningful human exposure route for potassium bromate. Acute high-dose ingestion (accidental or as an antiseptic, historically) causes severe acute renal tubular necrosis, irreversible hearing loss (selective cochlear damage), and GI toxicity — a distinct acute toxicity syndrome. At dietary exposure levels from residual bromate in finished bread, acute toxicity is not a concern; the risk is from long-term exposure and renal carcinogenesis. Bromate residuals in finished bread are reduced by: (1) complete baking at adequate temperature (>160°C) and sufficient time; (2) use of vitamin C (ascorbic acid) in dough, which competes as a reducing agent. Residual bromate risk varies substantially by baker: artisanal and industrial bakers who control bake temperature and time adequately have lower residuals. The Center for Science in the Public Interest (CSPI) has petitioned FDA multiple times (most recently 2020) to ban potassium bromate; FDA has not acted, citing insufficient evidence to mandate removal of a GRAS-listed substance.
What is potassium bromate?
Also known as: Bromic acid, potassium salt, potassium trioxobromate, 04MB35W6ZA, NSC-215200.
- IUPAC name
- potassium bromate
- CAS number
- 7758-01-2
- Molecular formula
- BrKO3
- Molecular weight
- 167.0 g/mol
- SMILES
- [O-]Br(=O)=O.[K+]
- PubChem CID
- 23673461
Risk for people
Moderate riskDietary ingestion via bromated flour bread products is the only meaningful human exposure route for potassium bromate. Acute high-dose ingestion (accidental or as an antiseptic, historically) causes severe acute renal tubular necrosis, irreversible hearing loss (selective cochlear damage), and GI toxicity — a distinct acute toxicity syndrome. At dietary exposure levels from residual bromate in finished bread, acute toxicity is not a concern; the risk is from long-term exposure and renal carcinogenesis. Bromate residuals in finished bread are reduced by: (1) complete baking at adequate temperature (>160°C) and sufficient time; (2) use of vitamin C (ascorbic acid) in dough, which competes as a reducing agent. Residual bromate risk varies substantially by baker: artisanal and industrial bakers who control bake temperature and time adequately have lower residuals. The Center for Science in the Public Interest (CSPI) has petitioned FDA multiple times (most recently 2020) to ban potassium bromate; FDA has not acted, citing insufficient evidence to mandate removal of a GRAS-listed substance.
Regulatory consensus
9 regulatory and scientific bodies have classified Potassium bromate. The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| IARC | 1999 | Group 2B (possibly carcinogenic to humans) | Classified as Group 2B based on sufficient evidence of carcinogenicity in experimental animals (renal cell tumors, peritoneal mesotheliomas, thyroid follicular cell tumors in rats) and inadequate evidence in humans. Potassium bromate is oxidatively genotoxic and forms 8-hydroxydeoxyguanosine DNA adducts; it induces oxidative stress in renal proximal tubule cells, the primary target organ. Although most bromate is destroyed by baking reactions (reducing to harmless bromide at temperatures >160°C with adequate oven time), residual bromate in finished bread has been detected. |
| EPA CTX / IARC | — | Group 2B - Possibly carcinogenic to humans | |
| EPA CTX / CalEPA | — | Known human carcinogen | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 7 positive / 0 negative reports) | |
| EPA CTX / Genetox | — | Genotoxicity: positive (Ames: positive, 7 positive / 0 negative reports) | |
| EPA CTX / Skin-Eye | — | Eye Irritation: Category 2B (score: moderate) | |
| EPA CTX / Skin-Eye | — | Eye Irritation: Category 6.4A (Category 2A) (score: high) | |
| EPA CTX / Skin-Eye | — | Skin Irritation: Category 6.3A (Category 2) (score: high) | |
| EPA CTX / Skin-Eye | — | skin sensitisation: in vivo (LLNA): Not likely to be sensitizing (score: low) |
Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.
Where you encounter potassium bromate
- Industrial Facilities — Manufacturing plants, Chemical storage areas, Waste treatment sites
- Occupational Environments — Factories, Warehouses, Transportation vehicles
- Food — processed food, beverages, candy, baked goods
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Potassium bromate:
-
Calcium carbonate or kaolin fillers
Trade-offs: Different performance characteristics than specialty fillers.Relative cost: 1.2-2×
Frequently asked questions
Is potassium bromate safe for you?
Dietary ingestion via bromated flour bread products is the only meaningful human exposure route for potassium bromate. Acute high-dose ingestion (accidental or as an antiseptic, historically) causes severe acute renal tubular necrosis, irreversible hearing loss (selective cochlear damage), and GI toxicity — a distinct acute toxicity syndrome. At dietary exposure levels from residual bromate in finished bread, acute toxicity is not a concern; the risk is from long-term exposure and renal carcinogenesis. Bromate residuals in finished bread are reduced by: (1) complete baking at adequate temperature (>160°C) and sufficient time; (2) use of vitamin C (ascorbic acid) in dough, which competes as a reducing agent. Residual bromate risk varies substantially by baker: artisanal and industrial bakers who control bake temperature and time adequately have lower residuals. The Center for Science in the Public Interest (CSPI) has petitioned FDA multiple times (most recently 2020) to ban potassium bromate; FDA has not acted, citing insufficient evidence to mandate removal of a GRAS-listed substance.
What products contain potassium bromate?
Potassium bromate appears in: Manufacturing plants (Industrial facilities); Chemical storage areas (Industrial facilities); Factories (Occupational environments); Warehouses (Occupational environments); processed food (Food).
Why do regulators disagree about potassium bromate?
Potassium bromate has been classified by 9 agencies including IARC, EPA CTX / IARC, EPA CTX / CalEPA, EPA CTX / Genetox, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.
See Potassium bromate in the food app
Look up products containing potassium bromate, compare to alternatives, and explore the full data record.
Open in food View raw API dataSources (3)
- IARC Monographs Volume 73: Some Chemicals that Cause Tumours of the Kidney or Urinary Bladder in Rodents and Some Other Substances — Potassium Bromate, Group 2B Classification, Renal Carcinogenicity, and 8-OHdG Oxidative DNA Damage Mechanism (1999) (1999) — academic
- US FDA: Potassium Bromate as Flour Improver — GRAS Status, Voluntary Withdrawal Policy, Residual Bromate in Finished Bread, and CSPI Petition History (2022) (2022) — regulatory
- EFSA: Potassium Bromate — EU Prohibition as Food Additive (1990), Residual Monitoring in Imported Bread Products, and IARC 2B Classification Review (2005) (2005) — regulatory
Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →