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Chapter 3: Builders and water softeners · Part 4: Chelating agents

Tetrasodium EDTA

  • Made from a hazardous chemical
  • Contaminant risk
Also called
EDTA, edetate
Found in
laundry liquid, cleaners, many cosmetics

The worst fact: it doesn't biodegrade in rivers or sewage plants. In Europe it's been found at higher concentrations in surface waters than any other man-made organic compound (a 2005 review cited by Australia's regulator in 2025), above 1,000 µg per litre in several countries. Australia has no river data, but sewage plant outflows have measured up to 210 µg per litre. Australia's regulator classes it as persistent.

Why brands use it: it locks up hard-water minerals and metals, which also keeps bleach stable.

Take care if: you get it in your eyes. Australia classes it as "Harmful if swallowed", "Causes serious eye damage" and "May cause respiratory irritation".

Comes from: ethylenediamine reacted with formaldehyde and sodium cyanide. 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: "EDTA is a preservative": no. It's a chelating agent.

Contaminants: NTA forms as a by-product of making it (see below). It's unlikely to matter in a well-made product, but it's a factor you can't see on the label.

Fair to say: Australia's regulator found no significant risk to the Australian environment, and sunlight breaks down iron-bound EDTA, often within hours to days. The EU Ecolabel bans it.

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.
  • AICIS. Evaluation statement EVA00169: EDTA and its salts (2025). IMAP assessments: trisodium phosphate (2016); etidronic acids (2013); soluble silicates (2016); nitrilotriacetic acid and salts (2017).
  • European Union. Regulation (EU) 259/2012 (phosphates in detergents); Detergents Regulation (EC) 648/2004, Annex VII; Regulation (EU) 2023/2055 (microplastics); EU Ecolabel decisions 2017/1216 and 2017/1218.
  • European Commission CSTEE. Opinion on the EU risk assessment of EDTA (2003).
  • HSDB (US National Library of Medicine), via PubChem: production, pH and impurity data for each chemical.
  • Nörtemann B. Biodegradation of EDTA. Appl Microbiol Biotechnol 1999;51:751-759.
  • Lanigan RS, Yamarik TA. Final report on the safety assessment of EDTA. Int J Toxicol 2002;21 Suppl 2:95-142.

The full source list is at the end of Chapter 3.