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Propylene Glycol

  • Glycol ether solvents
  • CAS 57-55-6
  • IUPAC: Propane-1,2-diol

Propylene Glycol (CAS 57-55-6) appears in 15 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is classified as a VOC.

Propylene glycol is a low-volatility diol with no GHS health hazard classification at typical use. It is GRAS-listed by the US FDA for food use, is not on California's Prop 65 list, and is not classified as a respiratory sensitizer (no H334), asthmagen, carcinogen, or reproductive toxicant. It is among the lower-concern co-solvents in car-care formulas.

Propylene glycol is a low-volatility diol with broad use as a humectant in cosmetics, food, pharmaceuticals, and air sanitizer formulas. It is GRAS-listed by the FDA for food use and is not on the Prop 65 list. Not classified as a respiratory sensitizer (no H334), not an asthmagen at consumer-product concentrations.

In Ozium-type air sanitizer aerosols, propylene glycol functions alongside triethylene glycol as the airborne sanitizing active — vaporized glycol micro-droplets remain suspended in cabin air for 3–4 hours and reduce airborne bacterial counts. The molecule itself has no acute inhalation toxicity at typical use concentrations, but the carrier system (propellant + IPA) is the dominant inhalation hazard, not the propylene glycol itself.

VOC: yes (730 g/L pure). At 1–5% in finished formulas, contributes 7–37 g/L absolute VOC — the majority of total VOC in glycol-aerosol products comes from co-solvent carriers (IPA, ethanol), not propylene glycol. Readily biodegradable per OECD 301B. Not aquatic-toxic at consumer-product release concentrations.

Health & environment profile

VOC
yes
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: Humectant and co-solvent — used in air sanitizer formulas as a glycol active that maintains airborne micro-droplets in the cabin atmosphere; in cleaning products as a freeze-resistant co-solvent and humectant

Common questions about Propylene Glycol

What is Propylene Glycol used for in car care?
Humectant and co-solvent — used in air sanitizer formulas as a glycol active that maintains airborne micro-droplets in the cabin atmosphere; in cleaning products as a freeze-resistant co-solvent and humectant
Is Propylene Glycol a VOC?
Yes. Propylene Glycol is classified as a volatile organic compound (VOC).
Is Propylene Glycol on California's Proposition 65 list?
No. Propylene Glycol is not on California's Proposition 65 list.
Is Propylene Glycol biodegradable?
Yes. Propylene Glycol has a confirmed biodegradable profile.

15 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.