α-Pinene
- Terpene solvents
- CAS 80-56-8
- IUPAC: (1S,5S)-2,6,6-Trimethylbicyclo[3.1.1]hept-2-ene
α-Pinene (CAS 80-56-8) appears in 2 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is classified as a VOC.
Skin and eye irritant; documented skin sensitizer (ACGIH lists for dermal sensitization). Oxidation products (peroxides) are the primary sensitization driver — exposure risk increases with bottle age. Inhalation at high concentration causes CNS effects.
α-Pinene is the most abundant monoterpene in pine resin and the dominant component of turpentine. It is included in penetrating oils as a natural co-solvent that lowers the formula's surface tension and improves wicking into tight clearances.
The chemistry is reactive. α-Pinene oxidizes on exposure to air to form hydroperoxides and other sensitizing compounds — the same chemistry that makes old turpentine bottles cause allergic skin reactions. ACGIH lists it specifically for dermal sensitization. Inhaled at high concentration, α-pinene causes headache, dizziness, and irritation of the upper respiratory tract.
Environmentally, α-pinene is naturally produced by living conifer trees in massive quantities — it is a major component of forest biogenic VOCs. It biodegrades readily, is not bioaccumulative (log Kow 4.83, below the 5.0 threshold), but it is acutely toxic to aquatic organisms at concentration and listed as a CERCLA Hazardous Substance (100 lb reportable quantity for spills).
Health & environment profile
- VOC
- yes
- Prop 65 listed
- no
- Asthmagen
- no
- EPA Safer Choice
- no
- Aquatic toxicity
- yes
- Biodegradable
- yes
- Bioaccumulative
- no
- Persistent
- no
- Ozone depleting
- no
- Microplastic
- no
- PFAS
- no
- Env. score
- 4/5
Common questions about α-Pinene
- What is α-Pinene used for in car care?
- Bicyclic monoterpene — natural penetrating co-solvent and pine-oil constituent
- Is α-Pinene a VOC?
- Yes. α-Pinene is classified as a volatile organic compound (VOC).
- Is α-Pinene on California's Proposition 65 list?
- No. α-Pinene is not on California's Proposition 65 list.
- Is α-Pinene biodegradable?
- Yes. α-Pinene has a confirmed biodegradable profile.
2 products contain this
CRC Knock'er Loose Penetrating SolventProp 65penetrating-oil
nextzett Blitz All Purpose CleanerProp 65all-purpose-cleaner
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.