WATCH — -4 pts

Caramel Color (Class III / Class IV)

Flags: F-Y06

Also known as: E150c, E150d, Ammonia caramel, Sulfite ammonia caramel

Kids Food & Snacks

What it is

Caramel color is the world's most widely used food coloring. There are four classes (I-IV). Class IV (sulfite ammonia caramel, E150d) is the most common and the one of concern: it contains 4-methylimidazole (4-MEI), a chemical byproduct formed during manufacturing.

WATCH

Class IV caramel color contains 4-MEI, which California's Office of Environmental Health Hazard Assessment (OEHHA) lists under Proposition 65 as a possible carcinogen. Animal studies demonstrated lung tumors from 4-MEI exposure. Most caramel color on labels does not specify which class is used.

Why it matters

4-MEI (4-methylimidazole): byproduct in Class IV caramel color, listed as possible carcinogen under California Prop 65
Lung tumors in mice at high 4-MEI doses (NTP study)
Label rarely specifies which class of caramel color is used
Ubiquitous: found in colas, soy sauce, baked goods, and many dark-colored processed foods

The research

Toxicology and Carcinogenesis Studies of 4-Methylimidazole

National Toxicology Program. NTP Technical Report 535, 2007. TR-535 [Source]

"NTP found clear evidence of carcinogenic activity of 4-MEI in male and female mice (increased incidence of alveolar/bronchiolar neoplasms)"

Who should care most

Consumers of products containing Class IV caramel color (most colas, dark sauces, some baked goods). Daily consumers face cumulative 4-MEI exposure.

How other countries handle it

Country	Status
United States	Permitted. California Prop 65 lists 4-MEI, requiring warning labels when daily intake exceeds 29 micrograms.
European Union	Permitted (E150a-d). Maximum limits set for 4-MEI content.
Canada	Permitted.
Australia	Permitted as E150a-d.

Sources

Toxicology and Carcinogenesis Studies of 4-Methylimidazole. National Toxicology Program. NTP Technical Report 535, 2007. TR-535. https://ntp.niehs.nih.gov/publications/reports/tr/500s/tr535

For informational purposes only. Not medical or dietary advice. Consult your pediatrician. Data current as of March 24, 2026.