Concerning naturally occurring fibrous silicate materials.

HB 2605 updates Washington State's definitions and regulations around naturally occurring fibrous silicate materials (like tremolite) in building materials. It clarifies that materials containing these minerals naturally - without chemical treatment - are not considered asbestos, and lowers the allowable asbestos content threshold in building materials from 1% to 0.25% by weight after January 1, 2025. The bill directly affects manufacturers, contractors, and facility owners (e.g., schools, offices) who handle or install building materials, requiring inspections and management plans for asbestos-containing materials. It also exempts commercial aggregates with low levels of naturally occurring minerals from stricter asbestos rules.