The one fact that drives everything: 1978
Lead-based paint was banned for residential use in 1978. Any house, apartment, or child-occupied facility (like a pre-school or daycare) built before 1978 is treated as potentially containing lead-based paint until testing proves otherwise.
Paint is "lead-based" if it contains lead at or above 1.0 mg/cm² or 0.5% by weight (5,000 ppm).
The trigger is building age — not how the building looks or how recently it was repainted. Newer paint often sits on top of old lead paint, and some imported materials still contain lead.
