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Cyclopentasiloxane (D5)

  • Silicones
  • CAS 541-02-6

Cyclopentasiloxane (D5) (CAS 541-02-6) appears in 5 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is classified as a VOC.

Low acute toxicity in normal car-care use. Eye irritation possible from direct contact. Animal studies show some endocrine signals at high doses — relevance to typical human consumer exposure is contested.

Cyclopentasiloxane (D5) is a volatile cyclic silicone widely used in car care as an evaporating carrier that leaves a silicone-rich film behind. Its environmental persistence has driven regulatory scrutiny in the EU, though US restrictions are limited.

Health & environment profile

VOC
yes
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
yes
Biodegradable
no
Bioaccumulative
yes
Persistent
yes
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
2/5
Purpose: Volatile cyclic siloxane carrier; evaporates after application leaving silicone-rich film. Common in waxes, tire dressings, and quick detailers

Common questions about Cyclopentasiloxane (D5)

What is Cyclopentasiloxane (D5) used for in car care?
Volatile cyclic siloxane carrier; evaporates after application leaving silicone-rich film. Common in waxes, tire dressings, and quick detailers
Is Cyclopentasiloxane (D5) a VOC?
Yes. Cyclopentasiloxane (D5) is classified as a volatile organic compound (VOC).
Is Cyclopentasiloxane (D5) on California's Proposition 65 list?
No. Cyclopentasiloxane (D5) 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.