An evaluation of one-time professional cleaning in homes with lead-based paint hazards.

A key challenge in reducing the burden of lead poisoning is to identify cost-effective interventions that minimize lead-based paint hazards. One-time professional cleaning of lead-contaminated dust and debris was conducted in 37 housing units with deteriorated lead-based paint and dust lead hazards. These study units are a subset of a larger cohort of the nearly 3500 housing units enrolled in the Evaluation of the HUD Lead-Based Paint Hazard Control Grant Program. Dust lead loading measurements were taken prior to cleaning, immediately after cleaning (i.e., clearance), and six months, one, two, and three years post-intervention. The cleaning intervention significantly reduced dust lead loadings on floors, windowsills, and window troughs immediately following the work. However, these reductions did not persist at six months and one year post-intervention. Six months and one year post-intervention dust lead loadings are not significantly different from the pre-intervention loadings on either bare floors or windowsills. Although window trough lead loadings declined over 50 percent from pre-intervention to one year post-intervention, the loadings rebounded markedly from the geometric mean at clearance of 101 microgram/ft(2) to 5500 microgram/ft(2) at 6 months and 5790 microgram/ft(2) at one-year post-intervention. These results demonstrate that a single professional cleaning of dust and debris without addressing potential sources of lead dust (such as deteriorated lead-based paint) or repeating the cleaning are unlikely to result in significant and sustained reductions in dust lead loadings. More extensive interventions that address deteriorated lead-based paint, although more expensive, are likely to provide longer term reductions in dust lead loadings. Cleaning strategies, however, may be useful in emergency situations to reduce lead dust hazards when paint repair and other lead hazard control activities cannot be done immediately.