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CarCareTruth

Sodium Metasilicate

  • Bases
  • CAS 6834-92-0
  • IUPAC: Sodium metasilicate

Sodium Metasilicate (CAS 6834-92-0) appears in 21 of the 2,122 car-care products CarCareTruth tracks (as of August 2026). It is readily biodegradable.

Causes severe skin burns (H314) and serious eye damage (H318) at concentrate strength. Strongly alkaline — pH approximately 12–13 in 1% solution. At 10:1 working dilution typical of detailing APCs, the working solution is moderately alkaline (pH 11–12) with H315 skin irritation and H319 eye irritation classifications rather than the corrosive Cat 1 classification. Inhalation of dust can irritate the respiratory tract; the dissolved liquid in finished APC formulas does not present the same dust hazard.

Sodium metasilicate is an inorganic alkaline builder commonly used in heavy-duty all-purpose cleaners and degreasers. It supplies hydroxide ions when dissolved in water, raising pH to 12–13 in the concentrate and providing the saponification chemistry that lifts greasy soils.

Why it matters in detailing APCs: Sodium metasilicate is the most common alkaline base in professional-line APCs (Meguiar's D101, Mothers Pro, Adam's standard APC). The "DANGER — causes burns" warning on the concentrate label typically traces to this ingredient. At working dilutions of 10:1 or weaker, the working solution is in the moderate-alkaline range (pH ~11–11.5) with significantly reduced skin/eye corrosion potential — the buyer never contacts the concentrate strength during normal use.

SDS alert: Check Section 3 for CAS 6834-92-0. When present at 1–5% in concentrate APCs, expect signal word DANGER on the concentrate label with H314 and H318. Working-solution chemistry should be evaluated separately per the concentrate-handling rule.

Regulatory status

  • Not CA Prop 65 listed
  • Listed on TSCA inventory; no specific use restrictions for consumer detailing APCs in the US
  • EU CLP classification: H290 (corrosive to metals), H314 (skin corrosion Cat 1B), H318 (serious eye damage)

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
5/5
Purpose: Alkaline builder and pH booster in degreasers and all-purpose cleaners; provides corrosion inhibition for some metal substrates

Common questions about Sodium Metasilicate

What is Sodium Metasilicate used for in car care?
Alkaline builder and pH booster in degreasers and all-purpose cleaners; provides corrosion inhibition for some metal substrates
Is Sodium Metasilicate a VOC?
No. Sodium Metasilicate is not classified as a volatile organic compound (VOC).
Is Sodium Metasilicate on California's Proposition 65 list?
No. Sodium Metasilicate is not on California's Proposition 65 list.
Is Sodium Metasilicate biodegradable?
Yes. Sodium Metasilicate has a confirmed biodegradable profile.

21 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.