Distillates, Petroleum, Hydrotreated Light Naphthenic

Hydrotreated light naphthenic petroleum distillates (CAS 64742-53-6) are a refined naphthenic lubricant fraction used as a carrier and viscosity modifier in multi-purpose lubricants, metalworking fluids, and aerosol sprays. The hydrotreating process saturates aromatic rings and removes most sulfur and PAH compounds, producing a lower-toxicity fraction than unrefined naphthenic stocks.

In multi-purpose lubricants this fraction contributes the residual oil film that keeps the mechanism lubricated after the lighter carrier evaporates. It has lower volatility than the lightest aliphatic fractions, so it persists on the surface longer — a meaningful contributor to lubrication longevity. Acute toxicity is low (oral and dermal LD50 >5000 mg/kg in standard rat/rabbit assays), and the substance is not classified as a skin or eye irritant on its own.

The H304 (aspiration hazard) classification is standard for low-viscosity petroleum fractions and reflects the risk of chemical pneumonitis if swallowed and aspirated into the lungs — not a vapor inhalation hazard during normal use. The Acute Tox. 4 (inhalation: dust, mist) classification applies to high-concentration mist exposure and informs the situational lungs PPE call for aerosol applications.