Hexamethyldisiloxane
- Silicones
- CAS 107-46-0
- IUPAC: hexamethyldisiloxane
Low acute toxicity. Flash point 4°C (flammable liquid Cat 1 at pure form). At <1% in finished formulations, acute hazard contribution is minimal. No skin sensitizer or respiratory sensitizer classification. GHS02 hazard is from flammability of the neat compound.
Hexamethyldisiloxane (HMDS, CAS 107-46-0) is a low-molecular-weight linear silicone solvent used in trace amounts in coating formulations as a carrier and diluent. It is more volatile than the high-molecular-weight cyclosiloxanes such as D5.
**Health:** Pure form is a flammable liquid (flash point 4°C). At <1% concentrations in a formulation, flammability hazard contribution is negligible. No GHS skin or respiratory sensitizer classification.
**Environment:** Moderate concern as a VOC in some jurisdictions. Not classified as bioaccumulative or aquatically toxic at trace concentrations. Lower environmental persistence than D5 due to faster environmental breakdown of linear vs. cyclic siloxanes.
Health & environment profile
- VOC
- yes
- Prop 65 listed
- no
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- no
- Biodegradable
- no
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 4/5
2 products contain this
Adam's Polishes Graphene Ceramic Spray CoatingProp 65hybrid-ceramic-spray
CarPro Cquartz UK 3.0ceramic-coating
Health summaries are editorial — we synthesize from SDSs, peer-reviewed sources, and regulatory listings. Not medical advice.