Chapter 3: Builders and water softeners · Part 2: Phosphonates
DTPMP
- Made from a hazardous chemical
The worst fact: a 2025 lab study in Nature Communications showed it can turn into glyphosate, the weedkiller, when it reacts with manganese minerals or dissolved manganese, including in wastewater. Up to 0.42% of it became glyphosate (and up to 27% became AMPA). How much this happens in real rivers isn't known.
Why brands use it: it keeps bleach stable and stops scale in laundry powder.
Take care if: you get it in your eyes. Most company reports class it as causing serious eye damage.
Comes from: phosphorous acid, an amine and formaldehyde. Australia classes formaldehyde as "May cause 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: nil.
Contaminants: nil.
Fair to say: the industry's risk assessment concluded that, despite some conflicting data, the weight of evidence suggests it isn't mutagenic.
Correct as of November 2026. What the badges mean
Sources
- Safe Work Australia. Hazardous Chemical Information System (HCIS): classifications for each chemical, and for formaldehyde.
- HERA. Risk assessments: STPP (2003) and STPP eutrophication note (2003); phosphonates (2004); zeolite A (2004); soluble silicates (2005); polycarboxylates parts I and II (2014).
- Röhnelt et al. Glyphosate formation from aminopolyphosphonates. Nat Commun 2025.
The full source list is at the end of Chapter 3.