Intact Lead Paint
Lead paint is considered to be intact if the painted surface is smooth and free of blisters, holes and cracks, and the paint is firmly attached to the surface and hard to dislodge. Old layers of intact lead paint that have been covered with unleaded paint are considerably less risky than exposed, deteriorating lead paint. However, the old paint remains a potential hazard even if its condition isn't an immediate threat, and should not be ignored. It may still serve as a source for lead-contaminated dust.
For instance, if the old paint is scraped or sanded to prepare it for repainting, heavily contaminated paint dust could be spread throughout the home. Therefore, as discussed above, only wet scraping or wet sanding techniques should be used, followed by thorough wet cleanup prior to repainting. Old lead paint on "friction" surfaces may remain a problem even if they've been repainted, because the new paint can get worn off over time, exposing the underlying lead paint and producing contaminated house dust. An apartment or house in which the old windows have been replaced may present less risk.