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Silicon Dioxide (SiO₂)

  • Ceramic (SiO₂)
  • CAS 7631-86-9
  • IUPAC: Silicon dioxide

Silicon Dioxide (SiO₂) (CAS 7631-86-9) appears in 5 of the 1,812 car-care products CarCareTruth tracks (as of June 2026).

Inert once cured. The inhalation concern is dose- and form-specific: aerosolized professional coatings (high SiO₂ %, solvent carrier, true atomized spray) warrant a respirator; dilute consumer pump-spray sealants (1-5% SiO₂ in water) do not. Defer to the product-level PPE block for the final call.

Silicon dioxide is the active ingredient in ceramic coatings. When applied as a nanoparticle suspension and allowed to cure, it forms a hard, glass-like layer that's extremely hydrophobic and resistant to chemical attack.

The cured coating is completely inert — it's literally glass. The health concern is during application only: SiO₂ nanoparticles suspended in solvent can be inhaled. Once cured (24-48 hours), there's zero ongoing health risk.

Environmentally, SiO₂ is abundant in nature (it's sand), but the nanoparticle form persists indefinitely. Not toxic, just persistent.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
no
Biodegradable
no
Bioaccumulative
no
Persistent
yes
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
4/5
Purpose: Ceramic coating active — forms hard hydrophobic layer

Common questions about Silicon Dioxide (SiO₂)

What is Silicon Dioxide (SiO₂) used for in car care?
Ceramic coating active — forms hard hydrophobic layer
Is Silicon Dioxide (SiO₂) a VOC?
No. Silicon Dioxide (SiO₂) is not classified as a volatile organic compound (VOC).
Is Silicon Dioxide (SiO₂) on California's Proposition 65 list?
No. Silicon Dioxide (SiO₂) is not on California's Proposition 65 list.

5 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.