Health hazard evaluation report: HETA-99-0113-2853, University of California, Berkeley, Berkeley, California.
At the request of the University of California, Berkeley, the National Institute for Occupational Safety and Health (NIOSH) conducted a study of lead-based paint (LBP) exposures during exterior renovation work on campus buildings. Workers' personal airborne lead (PbA) exposures were assessed for eight renovation tasks during a three-day demonstration project. Additionally we measured concomitant area PbA concentrations 6 feet (ft) from the work surfaces, lead in settled dust (PbS) at three distances (6, 10, and 20 ft) from work surfaces for five tasks, and determined if these measures were correlated with the workers' PbA exposures. Five workers performed assigned renovation tasks during limited work periods (average time 28 minutes [min]) on 22 painted exterior surface areas (wood windows, wood doors, and metal stairs). A total of 132 work periods were sampled; the work took from 2 to 12 work periods per designated work surface, depending on the area. Lead concentrations in paint chip samples (one per work surface) ranged from 0.23% to 34% lead (Pb) by weight (average 11.3%). Personal PbA exposures were highly variable; range, none detected to 660 micrograms per cubic meter ( g/m3), geometric mean (GM) = 22 g/m3, geometric standard deviation (GSD) 4.3. Personal PbA exposures were significantly associated with task, worker, and paint lead concentration (p <0.001). High-exposure tasks were dry manual sanding (GM = 49 g/m3), dry manual scraping (53 g/m3), power finish sanding (44 g/m3), and power finish sanding with bag (68 g/m3). Low-exposure tasks were power sanding with high-efficiency particulate air (HEPA) exhaust (GM = 6.9 g/m3), wet manual sanding (6.2 g/m3), wet manual scraping (16 g/m3), and flame burning (23 g/m3). The area PbA concentrations at 6 ft distance, which were also highly associated with task, were roughly an order of magnitude below the personal exposures, ranging from none detected to 37 g/m3, GM = 1.5 g/m3, GSD = 3.3. GMs for PbS samples were 3.2 milligrams per square meter (mg/m2) at 6 ft (n=69), 1.4 mg/m2 at 10 ft (n=67), and 0.66 mg/m2 at 20 ft (n=39). Overall PbS levels decreased significantly as distance increased (p <0.0001). At each distance PbS levels were significantly associated with task (p-values 0.024, 0.0015, and <0.0001, respectively). Flame burning was among the tasks associated with the highest area PbA and PbS levels, although personal exposures were relatively low. Surface paint lead concentrations were poorly correlated with the PbA exposures (R = 0.30). Personal and area PbA levels were significantly correlated (R = 0.49, p <0.0001). Both area and personal PbA concentrations were significantly correlated with PbS levels measured 6 ft and 10 ft from the work surfaces (R values 0.34 to 0.73). Area PbA levels were significantly correlated with the PbS levels at 20 ft as well (R = 0.67). Worker lead exposures for eight renovation tasks on building exteriors with LBP were highly variable. Based on workers' exposures, the eight renovation tasks evaluated fell into two exposure groups. Estimated average exposures during dry manual sanding, dry manual scraping, power finish sanding, and power finish sanding with bag would exceed the permissible exposure limit (PEL) within an 8-hr period. Estimated average exposures for power sanding with HEPA exhaust, flame burning, wet manual sanding, and wet scraping would be below the PEL. Although it resulted in relatively low worker exposures, flame burning was among the tasks associated with the higher lead levels in air and settled dust levels in nearby areas. The power finish sander with a cloth dust bag was not effective in controlling worker exposures; the random-orbital power sanding equipped with HEPA-filtered exhaust ventilation appeared to be highly effective. Recommendations are provided in this report to help prevent hazardous worker exposures to LBP during renovation of surfaces with LBP.