Chapter 11: The supporting cast · Part 3: Colours
Acid Green 25
- Made from a hazardous chemical
- Contaminant risk
The worst fact: the EU's safety committee (SCCS) assessed it only as a hair dye. Its use as a colourant "has not been assessed in this opinion". It isn't allowed in US food.
Why brands use it: a strong green.
Take care if: no specific group.
Comes from: quinizarin reacted with p-toluidine to make a green dye (D&C Green No. 6), which is then sulfonated. Australia classes p-toluidine as "Suspected of causing cancer". That doesn't mean it's in the product, but it's not a great starting point for something you clean with.
Myth check: "Green dye means plant colour": no. It's a synthetic anthraquinone dye.
Contaminants: p-toluidine (Australia: "Suspected of causing cancer"), limited in the US to 0.0015% (15 ppm), and up to 0.2% 1,4-dihydroxyanthraquinone. They're unlikely in a well-made product, but it's a factor you can't see on the label.
Fair to say: the SCCS found no risk at 0.3% in hair dye and "no in vivo genotoxic potential". The US EPA's Safer Choice list gives it a yellow triangle (allowed, with "some hazard profile issues").
Correct as of November 2026. What the badges mean
Sources
- Safe Work Australia. Hazardous Chemical Information System (HCIS): classifications for calcium chloride, boric acid, borax, and for N-vinylpyrrolidone, vinyl acetate, ethylene oxide, 1,4-dioxane, hydrazine, aniline, p-toluidine, styrene, chloromethane, carbon monoxide and octamethylcyclotetrasiloxane (D4).
- EU Scientific Committee on Consumer Safety. Opinion on Acid Green 25 (SCCS/1498/12).
The full source list is at the end of Chapter 11.