Health hazard evaluation report: HETA-99-0305-2878, Lead Safe Services, Inc., Neenah, Wisconsin.
At the request of a state-licensed contractor, the National Institute for Occupational Safety and Health (NIOSH) conducted a study of residential lead hazard reduction work. Workers’ task-specific and full-shift personal airborne lead (PbA) exposures were measured on three consecutive days during exterior work at two single-family homes in Oshkosh, Wisconsin. Tasks assessed were cleaning, demolition, dry scraping, component removal, set-up, and wet scraping. Additionally, we measured surface paint lead concentrations and, for dry scraping and a mix of other tasks, concomitant lead concentrations in settled dust (PbS) at 10, 15, and 25 feet (ft) (3.1, 4.6, and 7.6 meters [m]) from work surfaces. Mean exterior paint lead concentrations at the two houses were high: 22 percent (%) and 37% Pb by weight. The 79 task-specific worker PbA exposures measured were highly variable; range 1.4-2240 micrograms per cubic meter (microg/m3 ), geometric mean (GM) = 71 microg/m3 , geometric standard deviation (GSD) = 4.6. Within-task variability of PbA exposures was high (GSDs = 1.9-5.4). PbA exposures were significantly associated with task, worker, and house variables (p <0.0001). High-exposure tasks were cleaning (GM = 108 microg/m3 ), dry demolition (77 mcirog/m3 ), dry scraping (136 micorg/m3 ), and wet scraping (90 microg/m3 ); the means did not differ significantly in paired comparisons. The low-exposure task was set-up (GM = 12 microg/m3 ); the GM for removal also appeared to be low (30 microg/m3 ) but is uncertain due to small sample size (n = 3). Nearly all (14/15) of the full-shift PbA exposures collected for workers performing scraping and a mix of other tasks were above the permissible exposure limit (PEL) (GM = 100 microg/m3 , range: 39-526 microg/m3 ). Results for five full-shift area PbA samples collected to measure potential bystander exposures on work days were relatively low, ranging from 0.83 to 6.1 microg/m3 . Seventeen PbS samples collected at 10 ft (3.05 m), sixteen samples at 15 ft (4.57 m), and twelve samples at 25 ft (7.62 m) had respective GMs of 1716, 458 and 65 milligrams per square meter (mg/m 2 ). PbS levels were significantly associated with distance from the work surface, p <0.0005. PbS levels were not significantly associated with the two task categories (dry scraping and a mix of other tasks). Almost all of the full-shift PbA exposures for workers performing exterior scraping and a mix of other tasks were greater than the PEL. Task-specific PbA exposures were highly variable both within and between tasks. High-exposure tasks were cleaning, demolition, dry scraping, and wet scraping, with mean exposures exceeding the PEL. Mean exposures for set-up and component removal were below the PEL. The respirators used were adequate to protect workers from the exposures measured. Recommendations are provided in this report to assist the contractor in controlling worker exposures to hazardous levels of lead-based paint.