Mineral Spirits

Mineral spirits (CAS 64742-88-7) — also marketed as Stoddard Solvent or hydrotreated heavy naphtha — is a mid-boiling-range petroleum distillate used as a carrier solvent and abrasive dispersant in polishes, waxes, and cleaners. It is distinct from odorless mineral spirits (CAS 64741-65-7, which has lower aromatic content) and from hydrotreated light petroleum distillates (CAS 64742-47-8).

In glass and paint polishes, mineral spirits suspends abrasive particles (cerium oxide, aluminum oxide) and facilitates their release onto the substrate during polishing. It evaporates slowly, giving working time, and typically does not leave residue on well-buffed surfaces.

Mineral spirits itself is not California Prop 65 listed. Some finished products carrying mineral spirits display a Prop 65 warning; where that happens, the actual regulatory basis is trace aromatic hydrocarbons, particularly cumene (isopropylbenzene, a separately listed carcinogen with its own CAS number and its own ingredient file), present in the stoddard-solvent fraction of the complex petroleum mixture, not mineral spirits (CAS 64742-88-7) as a listed substance in its own right. The hydrotreatment process removes many polynuclear aromatics but does not fully eliminate lighter aromatics like cumene. A product whose SDS discloses cumene as a distinct, quantified component should carry that as a separate ingredient entry rather than inheriting the flag onto this file.

Aquatic toxicity at ingredient level is documented independent of the Prop 65 question: LC50 (fish, 96hr) 45 mg/L emulsified in EPA data. The mixture-level classification in finished products depends on dilution and formulation.

Regulatory status

• Not California Prop 65 listed: no entry for mineral spirits, Stoddard solvent, or CAS 64742-88-7 on the OEHHA list. Multiple manufacturer SDS documents for mineral spirits and Stoddard solvent confirm the same conclusion (no Prop 65 chemicals in the product as sold). A prior version of this file asserted prop65_listed: true on the basis of trace cumene content, which is a different, separately listed substance, not this one.

Sources

• OEHHA Proposition 65 list cross-check: data/prop65/oehha-list.json (986 entries, published 2025-12-05), no entry by name or CAS 64742-88-7. Cumene (CAS 98-82-8) confirmed present in the same file (cancer, listed 2010-04-06), consistent with the trace-impurity mechanism described above but confirming it belongs to cumene's own identity, not mineral spirits'.
• Blast-radius check across all 11 products currently referencing this ingredient file: adams-polishes-buttery-wax (Prop 65 driven independently by diethanolamine, 0.047%, SDS §15), goof-off-pro-strength-overspray-remover (driven independently by ethylbenzene, SDS §15), meguiars-gold-class-liquid-wax (driven independently by an Amazon-posted warning for trace petroleum-distillate constituents), rust-oleum-rust-reformer (driven independently by an Amazon-posted warning plus ethylbenzene/carbon black), and griots-garage-glass-polish (currently cites mineral spirits' trace cumene content as the SDS-side basis in its FAQ copy, but the product body text separately states the warning is also confirmed via Amazon product data, an independent arm). None of these products' published prop65_warning values change from this correction. griots-garage-glass-polish's FAQ rationale is now stale in the same way the ammonium-bifluoride/meguiars-wheel-brightener case was: the resolved value is still correct, but the stated chemistry basis should be corrected on a future regen (out of scope here; product files are not owned by this pass). The remaining 6 referencing products already resolve prop65_warning: false and are unaffected.