Quartz (Crystalline Silica)

Quartz (CAS 14808-60-7) is the crystalline form of silicon dioxide (SiO₂), one of the most abundant minerals in Earth's crust. In anti-seize pastes, it appears at trace concentrations (typically <1–5%) as a naturally occurring component of the mineral fillers used in the formulation.

The primary health concern for crystalline silica is occupational inhalation of respirable-size particles (PM10 or finer) during activities that generate silica dust — mining, sandblasting, cutting stone, and demolition. Chronic inhalation causes silicosis (progressive fibrous scarring of lung tissue) and significantly elevates lung cancer risk. This has led to IARC Group 1 (human carcinogen) and NTP Known Human Carcinogen designations, and to California Prop 65 listing for cancer.

In anti-seize compounds, the quartz is fully encapsulated in a petroleum-grease carrier and does not generate respirable dust during normal brush application. Henkel's own SDS §11 for Loctite LB 8008 explicitly states: "The crystalline silica present in this product is encapsulated in the liquid and will only be liberated if the product is sanded or abraded." The H372 STOT RE Cat 1 classification at the product level is a regulatory requirement based on the ingredient's known occupational hazard profile, not a reflection of the inhalation risk during normal paste application. The classification is required by OSHA HCS when the ingredient exceeds certain concentration thresholds in the mixture.