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Chapter 11: The supporting cast · Part 5: Antifoams

Dimethicone and silicone antifoam

  • Made from a hazardous chemical
  • Contaminant risk
Also called
dimethicone, polydimethylsiloxane (PDMS), silicone, simethicone, E900
Found in
front-loader laundry detergent, dishwasher detergent

The worst fact: making it also makes cyclic siloxanes (D4, D5, D6), which the EU names "very persistent and very bioaccumulative". Since 7 June 2026 the EU has banned products, including cleaners, that contain 0.1% or more of D4, D5 or D6 (some cosmetics, medicines and medical devices have later dates). Australia classes D4 as "Suspected of damaging fertility".

Why brands use it: it's a defoamer.

Take care if: no specific group. The Poisons Standard lists dimethicone as not needing control, for low toxicity.

Comes from: silicon reacted with chloromethane, then hydrolysed. Australia classes chloromethane 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: "Silicone builds up in your body": swallowed, more than 99.9% passes out unchanged.

Contaminants: D4 (Australia: "Suspected of damaging fertility."), D5 and D6, formed in the same step. The EU food safety authority said they "could contaminate the final product". They're unlikely in a well-made product, but it's a factor you can't see on the label.

Fair to say: the silica in silicone antifoams is a factory-made (synthetic amorphous) silica, precipitated or fumed and coated to repel water. Amorphous silica is "not classifiable" as a carcinogen by the WHO's cancer agency, unlike crystalline silica dust. Swallowed, dimethicone is almost entirely excreted unchanged, and the EU found "no safety concern" as a food additive.

Correct as of November 2026. What the badges mean

Sources

  • Australian Government. Poisons Standard October 2026 (SUSMP), F2026L01327: boric acid; sodium stannate; formic acid; Appendix B (dimeticone).
  • 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).
  • NICNAS/AICIS. IMAP Tier II assessments: boric acid and borates; titanium dioxide (2016); octamethylcyclotetrasiloxane (D4); decamethylcyclopentasiloxane (D5).
  • European Union. Regulation (EC) 1333/2008 Annex V; Regulation (EU) 231/2012 (food additive specifications); Regulation (EU) 2022/63 (E171); Regulation (EU) 1297/2014 (detergent capsules); Regulation (EC) 790/2009 and Delegated Regulation (EU) 2021/849 (borates); Regulation (EU) 109/2012; Regulation (EU) 2023/2055 (microplastics); Regulation (EU) 2024/1328 (D4, D5, D6); Regulation (EC) 1223/2009 (cosmetics) Annexes III and IV.
  • EFSA. Re-evaluations of xanthan gum (E415, 2017, 2023), guar gum (E412, 2017), dimethyl polysiloxane (E900, 2020); titanium dioxide (E171, 2021).

The full source list is at the end of Chapter 11.