Potassium Bromate: Why Is It Banned in So Many Countries?
What potassium bromate is, why it's added to flour and bread, why it's banned in the EU, UK, Canada and China but still allowed in the US, and how to avoid it.
Potassium bromate is added to flour to make bread rise higher and look whiter and softer. It’s one of the best-known additives that are banned in many countries but still allowed in the US. The reason: it causes cancer in animals.
The short answer: potassium bromate is a chemical that makes dough stronger. In rats, it causes kidney, thyroid and other tumors and damages DNA. The International Agency for Research on Cancer says it can possibly cause cancer in humans. It’s banned in the EU, UK, Canada, China, Brazil and India. In the US, the FDA still allows it, but it has asked bakers to stop using it since 1991. California will ban it from 2027. Most of it should break down during baking, but leftovers have been found in bread.
What is potassium bromate?
Potassium bromate is a chemical that makes the gluten in dough stronger. With it, bread dough is stretchier, holds more air, rises higher and bakes into a soft, white, fluffy loaf. It’s been used since the early 1900s, mainly in store-bought white bread.
During baking, potassium bromate is supposed to turn into bromide, which is much less harmful. But this only fully happens if the right amount is used and the bread is baked long and hot enough.
On labels, you’ll see it as potassium bromate or bromated flour.
Which foods contain potassium bromate?
In countries where it’s allowed (mainly the US), you may find it in:
- White bread and sandwich bread
- Hamburger and hot dog buns
- Rolls, bagels and pizza dough
- Tortillas and flatbreads
- Bromated flour sold for home and professional baking
Many large US bakeries have stopped using it, but it’s still found in some products.
Why is potassium bromate banned?
Cancer in animals
Scientists in Japan gave potassium bromate to rats. The rats got kidney tumors, thyroid tumors and tumors in the lining of the belly. The scientists called it a “complete carcinogen”: it can both start cancer and help it grow. They also showed that it damages DNA (Kurokawa et al., Environmental Health Perspectives, 1990). Later studies found the same DNA damage in rat kidneys, and kidney tumors at several doses (Umemura et al., Toxicology, 2006).
The International Agency for Research on Cancer says potassium bromate can possibly cause cancer in humans (Group 2B).
Testing on purpose whether a substance causes cancer in people would put their health at risk. That’s why animal studies are used. Rats share most of their genes with us, and their bodies work in many of the same ways. Bromate also harms the kidneys of people who have swallowed large amounts by accident.
Leftovers in bread
Some say potassium bromate is fine because it breaks down during baking. But studies have found leftover bromate in bread:
- In Bangladesh, 67% of bread samples from bakeries and shops had more bromate than other countries allow (Mahmud et al., Food Science & Nutrition, 2021).
- Leftover bromate has also been found in bread in Tunisia and other countries (El Ati-Hellal et al., Environmental Science and Pollution Research, 2018).
Leftovers are more likely when too much is used or the bread isn’t baked enough.
Where is potassium bromate banned?
| Country/region | Status |
|---|---|
| European Union and UK | Banned |
| Canada | Banned |
| China | Banned (since 2005) |
| Brazil, India and many others | Banned |
| United States | Allowed; FDA has asked bakers to stop voluntarily since 1991 |
| California | Cancer warning required; banned in food from 2027 |
How to avoid potassium bromate
- Read labels on bread, buns, rolls and bagels – look for “potassium bromate” or “bromated flour”.
- Choose bread labeled “unbromated” or made with unbromated flour.
- Buy bread from bakeries that use simple ingredients – flour, water, yeast and salt.
- Choose whole-grain bread, which rarely uses bromate.
- If you bake at home, buy unbromated flour.
Spot potassium bromate on any label in seconds. With NutriSmart, you photograph the ingredient list or scan the barcode, and the app tells you right away if the product has potassium bromate. Turn on an alert for it, and the app warns you every time a product you scan contains it. You’ll also see every other additive, the risks of each one and a health score out of 100.Get the app free
You can also read about other bread additives: calcium propionate and mono and diglycerides.
The bottom line
Potassium bromate makes bread rise higher and look whiter. But it causes cancer and DNA damage in animals, and it can possibly cause cancer in humans. That’s why it’s banned in the EU, UK, Canada, China and many other countries. California will ban it from 2027. It should break down during baking, but leftovers have been found in bread. There’s no reason to accept it – choose unbromated bread and flour.
FAQ
What is potassium bromate?
Potassium bromate is a chemical added to flour to make dough stronger and stretchier. Bread then rises higher and is soft and white inside. It's used mainly in store-bought white bread, buns, rolls and bagels.
Why is potassium bromate banned?
Because it causes cancer in animals. In rats, it caused kidney, thyroid and other tumors, and it damages DNA. The International Agency for Research on Cancer says it can possibly cause cancer in humans. It's banned in the EU, UK, Canada, China, Brazil, India and many other countries.
Is potassium bromate banned in the US?
Not in the whole country. The FDA still allows it, but since 1991 it has asked bakers to stop using it on their own. California requires a cancer warning on products with it. It also passed a law banning it in food from 2027. Other states have proposed similar bans.
Doesn't potassium bromate disappear during baking?
Most of it is supposed to turn into harmless bromide during baking. But if too much is used, or the bread isn't baked long or hot enough, some is left over. Studies in several countries have found leftover bromate in many bread samples.
How do I know if bread contains potassium bromate?
Check the ingredient list for "potassium bromate" or "bromated flour". In the EU, UK and Canada it isn't allowed, so bread there shouldn't contain it.
What is E924?
E924 was the European code for potassium bromate. It's no longer authorized as a food additive in the EU.
