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Ammonium Thioglycolate

  • Reducers
  • CAS 5421-46-5
  • IUPAC: Ammonium 2-mercaptoacetate

Ammonium Thioglycolate (CAS 5421-46-5) appears in 4 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is readily biodegradable.

Strong sulfur odor. Skin and eye irritant — wear gloves. The 'perm solution' smell is characteristic. Not systemically toxic at car-care concentrations.

Ammonium thioglycolate is the active ingredient in color-change wheel cleaners (SONAX Full Effect, Iron-X, etc.). It reacts with iron oxide (brake dust) to form a purple iron-thioglycolate complex — giving you visible feedback that the product is working.

The distinctive sulfur smell is unavoidable — it's the same chemistry used in hair perms. Wear nitrile gloves (it's a skin irritant) and avoid spraying into the wind. The purple runoff should go to a sanitary drain, not a storm drain — the compound is moderately aquatic-toxic before it breaks down.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
yes
Biodegradable
yes
Bioaccumulative
no
Persistent
no
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
3/5
Purpose: Iron decontamination (brake dust indicator)

Common questions about Ammonium Thioglycolate

What is Ammonium Thioglycolate used for in car care?
Iron decontamination (brake dust indicator)
Is Ammonium Thioglycolate a VOC?
No. Ammonium Thioglycolate is not classified as a volatile organic compound (VOC).
Is Ammonium Thioglycolate on California's Proposition 65 list?
No. Ammonium Thioglycolate is not on California's Proposition 65 list.
Is Ammonium Thioglycolate biodegradable?
Yes. Ammonium Thioglycolate has a confirmed biodegradable profile.

4 products contain this

Related

Health and environment notes translate the manufacturer Safety Data Sheet, the GHS classification, and authoritative regulatory listings (California Prop 65, EPA). Not medical advice. They describe the ingredient itself; whether a hazard applies to a finished product depends on its concentration and how it's used.