1-Methylnaphthalene
- Aromatic solvents
- CAS 90-12-0
- IUPAC: 1-Methylnaphthalene
1-Methylnaphthalene (CAS 90-12-0) appears in 1 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is classified as a VOC.
IARC Group 2B (possibly carcinogenic to humans) via inhalation. Secondary isomer of 2-methylnaphthalene. Together with 2-methylnaphthalene contributes to the mixture-level H350 carcinogenicity classification in products containing PAH solvent fractions.
1-Methylnaphthalene (CAS 90-12-0) is the 1-position isomer of methylnaphthalene, paired with 2-methylnaphthalene (CAS 91-57-6) in petroleum-derived aromatic solvent fractions. In AMSOIL Power Foam it appears at 1–<5%. Both methylnaphthalene isomers are PAH compounds occurring naturally in coal-tar and crude-oil refinery streams.
The environmental and health profile of 1-methylnaphthalene parallels that of its 2-isomer counterpart: aquatic toxicity, bioaccumulation potential, and IARC Group 2B carcinogenicity classification. Both isomers together with naphthalene itself form the PAH solvent backbone that drives the mixture-level H350 classification in the AMSOIL SDS.
In aerosol cleaning applications, 1-methylnaphthalene contributes to deposit solvency for heavy carbon and varnish buildup in induction passages and carburetor circuits.
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
Common questions about 1-Methylnaphthalene
- What is 1-Methylnaphthalene used for in car care?
- Polycyclic aromatic hydrocarbon (PAH) solvent fraction — isomer partner to 2-methylnaphthalene — present in petroleum-derived aerosol cleaners including induction-system cleaners. Contributes solvency for carbon and varnish deposits.
- Is 1-Methylnaphthalene a VOC?
- Yes. 1-Methylnaphthalene is classified as a volatile organic compound (VOC).
- Is 1-Methylnaphthalene on California's Proposition 65 list?
- No. 1-Methylnaphthalene is not on California's Proposition 65 list.
1 product contain this
AMSOIL Power Foam Engine Cleaner and DegreaserProp 65engine-degreaser
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.