Skip to content
CarCareTruth

Propylene Glycol Butyl Ether

  • Glycol ether solvents
  • CAS 5131-66-8
  • IUPAC: 1-Butoxypropan-2-ol

Propylene Glycol Butyl Ether (CAS 5131-66-8) appears in 5 of the 2,122 car-care products CarCareTruth tracks (as of August 2026). It is classified as a VOC.

Low acute toxicity. OSHA PEL 200 ppm (8h TWA) for the related glycol ether class; PGBE has no specific OSHA/NIOSH/ACGIH limits per SDS data. Skin and eye irritant at high concentrations; not classified at consumer product levels.

Propylene glycol butyl ether (PGBE) is a glycol ether co-solvent used in water-based cleaning formulations. It improves penetration of the formula into surface contamination, aids wetting, and helps maintain solution stability. Unlike older glycol ethers in the E-series (ethylene glycol-based), the P-series glycol ethers (propylene glycol-based) are considered lower-risk — they do not produce the toxic metabolite methoxyacetic acid that makes E-series ethers reproductive hazards.

At the 1–3% concentrations typically used in wheel cleaners and detailing products, PGBE contributes minimally to VOC content but provides measurable performance benefit as a coupling agent. It is biodegradable and has low aquatic toxicity at typical use 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
3/5
Purpose: Glycol ether co-solvent — aids penetration, cleaning performance, and formula stability in water-based cleaners

Common questions about Propylene Glycol Butyl Ether

What is Propylene Glycol Butyl Ether used for in car care?
Glycol ether co-solvent — aids penetration, cleaning performance, and formula stability in water-based cleaners
Is Propylene Glycol Butyl Ether a VOC?
Yes. Propylene Glycol Butyl Ether is classified as a volatile organic compound (VOC).
Is Propylene Glycol Butyl Ether on California's Proposition 65 list?
No. Propylene Glycol Butyl Ether is not on California's Proposition 65 list.
Is Propylene Glycol Butyl Ether biodegradable?
Yes. Propylene Glycol Butyl Ether has a confirmed biodegradable profile.

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.