Potassium Bromate: Banned Almost Everywhere, Still in US Bread

Potassium bromate (E924) makes dough stronger and bread rise higher, taller, and cheaper. It's also a possible human carcinogen that most of the world banned decades ago — and it can still legally appear in American bread.

Why almost everyone else said no

Potassium bromate is classified by the WHO's cancer agency (IARC) as Group 2B — possibly carcinogenic to humans, based on animal studies showing tumors. The theory is that proper baking converts the bromate into harmless bromide — but if a baker uses too much, or underbakes, measurable carcinogenic residue can remain in the finished loaf. Rather than police that, most countries simply banned it.

A cheaper, fluffier loaf — at the cost of a possible carcinogen the rest of the world decided wasn't worth it.

What to know

• It's a processing aid — purely to strengthen dough and speed production; it adds nothing for you.
• IARC Group 2B — possibly carcinogenic; the concern is residual bromate in under-baked or over-treated bread.
• Banned widely — the EU, UK, Canada, Brazil, China, and others prohibit it in food.
• The US is moving — California's 2023 Food Safety Act (AB418) bans it statewide effective 2027, alongside Red 3 and BVO.
• It's avoidable — many US bakers already skip it; "no bromate / bromate-free" appears on cleaner labels.

The honest assessment

This is one where the global consensus is hard to argue with: a possible carcinogen, used only to cut cost, that nearly every other developed country banned. The realistic risk from one sandwich is small, but there's no upside to you in it — and the fact that it's still federally legal in the US while the rest of the world (and now California) bans it is exactly the kind of gap worth seeing on a label.

Sources: IARC monographs (potassium bromate, Group 2B) · EU/UK/Canada/Brazil/China food-additive prohibitions · US FDA flour-additive status · California AB418 (2023), effective 2027.

TrueFood provides educational information about food ingredients and is not medical advice. Regulatory status varies by country and changes over time; current to the cited sources.