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Chapter 2: Other surfactants · Part 2: Cationic surfactants (fabric softeners)

DHTDMAC

No badge

Also called
dihydrogenated tallow dimethyl ammonium chloride, DTDMAC, ditallow dimethyl ammonium chloride ·
Found in
older fabric softeners

The worst fact: at about 0.01 mg per litre measured in the River Rhine, it was "likely to have biological consequences". In 1991 the Dutch government's health institute reported an agreement to ban it from fabric softeners.

Why brands use it: for many years softeners "were almost exclusively based on" it.

Take care if: it could splash in your eyes. Australia classes its close relative DODMAC as "Causes serious eye damage".

Comes from: hydrogenated tallow amines, probably finished with methyl chloride (according to a US chemical database, for a close relative). Without a firmer reference, this book gives no 🛢 badge.

Myth check: "It's still in your softener": in the 1990s it was voluntarily replaced in several countries by esterquats, and Australia's regulator found no specific Australian use information for it.

Contaminants: nil.

Fair to say: it's "efficiently removed from wastewater", and later studies (from 2001) suggest it breaks down better in the environment than first thought, though it didn't break down at all in a test without oxygen.

Correct as of November 2026. What the badges mean

Sources

  • Safe Work Australia. Hazardous Chemical Information System (HCIS): classifications for alcohol ethoxylates, C10-12 alcohol EO/PO, cocamidopropyl betaine, nonylphenol, DODMAC, and for ethylene oxide, propylene oxide, dimethyl sulfate, methyl chloride, benzyl chloride, epichlorohydrin, DMAPA, monochloroacetic acid and 1,4-dioxane.
  • NICNAS/AICIS. IMAP Tier II assessments: ethoxylated aliphatic alcohols (2019); alkoxylated aliphatic alcohols (2020); nonylphenols; nonylphenol ethoxylate sulfate and phosphate esters (environment, 2016); cationic surfactants; mono- and dialkyl quaternary ammonium compounds (environment, 2016); cocamidopropyl betaine; fatty acid amidopropyl dimethylamines. Public reports STD/1386 (esterquat, 2011) and STD/1363 (lauryl hydroxysultaine).
  • RIVM (Netherlands). DTDMAC in surface and drinking water (1991).
  • Danish EPA. Household detergents, chapter 5: cationic surfactants (2001).
  • HSDB (US National Library of Medicine), via PubChem, including Gosselin, Clinical Toxicology of Commercial Products (1984); ECHA C&L Inventory (company notifications, via PubChem); JECFA, sodium oleate (via PubChem).
  • Garcia MT et al. Anaerobic degradation of cationic surfactants. Chemosphere 2000.

The full source list is at the end of Chapter 2.