Sodium Thioglycolate
- Reducers
- CAS 367-51-1
- IUPAC: Sodium 2-mercaptoacetate
Sodium Thioglycolate (CAS 367-51-1) appears in 10 of the 2,122 car-care products CarCareTruth tracks (as of August 2026). It is readily biodegradable.
Sulfur odor. Skin and eye irritant at concentration (H315, H319). Harmful if swallowed (H302, LD50 oral mouse 504 mg/kg). Sodium salt form appears milder than ammonium thioglycolate at consumer product-level classification.
Sodium thioglycolate is the sodium salt of thioglycolic acid — the same iron-reactive chemistry as ammonium thioglycolate but using sodium as the counterion. It reacts with iron oxide (brake dust) to form a purple iron-thioglycolate complex, providing visible feedback that decontamination is occurring.
Used in Griot's Garage Iron & Fallout Remover at 25% concentration. At the product level, Griot's SDS classifies the mixture as WARNING with H302/H315/H319 only — notably milder than products using ammonium thioglycolate at similar concentrations, which typically carry DANGER with H318 (serious eye damage) and H312 (harmful in contact with skin). Whether this reflects the salt form, concentration effects, or formulation choices is not clear from the SDS alone.
Aerobically biodegradable in wastewater treatment. The purple iron-thioglycolate runoff from wheel cleaning should go to sanitary sewer, not storm drain, as a general best practice for iron-remover rinse water.
Health & environment profile
- VOC
- no
- Prop 65 listed
- no
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- no
- Biodegradable
- yes
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 4/5
Common questions about Sodium Thioglycolate
- What is Sodium Thioglycolate used for in car care?
- Iron decontamination (brake dust indicator)
- Is Sodium Thioglycolate a VOC?
- No. Sodium Thioglycolate is not classified as a volatile organic compound (VOC).
- Is Sodium Thioglycolate on California's Proposition 65 list?
- No. Sodium Thioglycolate is not on California's Proposition 65 list.
- Is Sodium Thioglycolate biodegradable?
- Yes. Sodium Thioglycolate has a confirmed biodegradable profile.
10 products contain this
3D Car Care BDX Iron Remover (16 oz)iron-remover
3D Car Care GLW Series Iron Remover (1 Gallon)iron-remover
Griot's Garage Heavy-Duty Wheel Cleanerwheel-cleaner
Gtechniq W6 Iron and General Fallout Removeriron-remover
Meguiar's Ultimate Iron Remover (24 oz)iron-remover
Optimum FerreX Iron Removeriron-remover
Prop 65
Sonax Beast Wheel Cleaner (1 Liter)wheel-cleaner
Sonax Full Effect Wheel Cleaner (500 ml)wheel-cleaner
Prop 65
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.