Residential and commercial painters' exposure to lead during surface preparation

The California Painters Project was a 2-year intervention research project aimed at preventing lead poisoning among a group of residential and commercial painters in San Francisco, Calif. As part of this project 12 contractors invited project staff to conduct employee exposure monitoring. Twenty-five full-shift samples were collected, with 8-hr TWA results ranging from 0.8 to 550 microg/m3 (arithmetic mean: 57 microg/m3). Six of the 25 samples (24%) were above the Occupational Safety and Health Administration (OSHA) permissible exposure limit; all of these involved dry manual sanding or uncontrolled power sanding. Fifty-eight 30-minute task-specific samples also were collected. The arithmetic mean concentration results for heat gun use, wet sanding, and open flame burning were all under 10 microg/m3; the mean concentration for HEPA-exhausted power sanding was 33 microg/m3; dry manual scraping, 71 microg/m3; dry manual sanding, 420 microg/m3; and uncontrolled power sanding, 580 microg/m3. Analysis and modeling based on the 30-min results for dry manual sanding and uncontrolled power sanding indicate that painters' full-shift exposures often exceed 500 microg/m3 and the OSHA assigned level of protection for a half-mask air-purifying respirator. These results are cause for concern because both of these surface preparation methods are widely performed wearing half-mask respirators. The data show that HEPA-exhausted power sanding reduces paint dust exposure levels by approximately 80 to 90%. These tools should be more widely promoted as a safer alternative work method.