On March 31, 2003, the National Institute for Occupational Safety and Health (NIOSH) received a request for a health hazard evaluation (HHE) from the United Union of Roofers, Waterproofers, and Allied Workers Local 135 at Diversified Roofing Inc. in Phoenix, Arizona. The request stated that employees were exposed to hazardous levels of dust, particularly crystalline silica, while cutting cement tiles. A concern was also raised about the lack of training and use of personal protective equipment. An initial site visit was conducted on April 29-30, 2003. This visit included observations of the tile cutting process, collection of bulk samples of tile dust, and spot measurements of dust, noise, and carbon monoxide (CO) levels. A second site visit was conducted on June 16-18, 2003. Respirable and total dust, respirable silica, noise, and CO were monitored on employees performing roof installation. All employees who were monitored were asked questions on general health symptoms, work practices, and use of personal protective equipment. Eight full-shift personal noise samples, eight full-shift personal breathing zone (PBZ) air samples for CO, sixteen full-shift PBZ air samples for respirable dust and silica, and nineteen full-shift PBZ air samples for total dust were collected over the 2 days. The noise exposure results showed that all of the employees' exposures were over the NIOSH Recommended Exposure Limit (REL), 63% (5 of 8) exceeded the Occupational Safety and Health Administration (OSHA) Action Level, and 38% (3 of 8) were over the OSHA Permissible Exposure Limit (PEL) for noise. The CO exposure results showed that all of the employees' exposures were below the REL time-weighted average

one employee's exposure exceeded the NIOSH ceiling level. The respirable silica (quartz) exposure results showed that 88% (14 of 16) of the employees' levels exceeded the NIOSH REL and American Conference of Governmental Industrial Hygienists threshold limit value, and 75% (12 of 16) exceeded the OSHA PEL for respirable silica. The total dust exposures ranged from 0.68 milligrams per cubic meter (mg/m3) to 13 mg/m3. The respirable dust exposures ranged from 0.23 mg/m3 to 2.3 mg/m3. During the initial site visit informal employee interviews revealed that the duration of employment ranged from a few weeks to 7 years. Most of the employees reported wearing hard hats and eye protection regularly

respirators and hearing protection were infrequently worn. None of the employees reported that they knew the hazards of silica overexposure even though some employees reported respiratory symptoms consistent with silica overexposures, such as difficulty breathing and/or cough. A follow-up visit was conducted February 22-24, 2005, to perform the medical screening component of the HHE. Employees were invited to participate if they had at least 5 years experience as a roofer. Duration of dry cutting was used as a marker for duration of respirable silica exposure. The medical screening included a questionnaire, lung function test (i.e., spirometry), and a chest x-ray. NIOSH personnel read the questionnaire aloud to participants in their primary language. Spirometry results were reviewed by a NIOSH pulmonologist. The chest x-rays were interpreted by NIOSH certified B-readers according to the standards set forth by the International Labor Organization for grading work-related lung disease chest x-rays. Most roofers who participated in the medical screening had normal lung function. Of those with abnormal lung function, none had moderate or severe impairments. After controlling for the effects of smoking, it was found that lung function decreased with increasing years of dry cutting cement tiles. No chest x-rays showed findings consistent with silicosis. Previous air sampling confirmed that all employees on the roof when tile cutting was occurring could be overexposed to respirable silica, placing them at risk for silicosis. It is vital to institute OSHA-mandated employee protection programs to protect workers from further exposure to respirable silica. Employee monitoring for silicosis should also be started as per the recommendations set forth in OSHA's Special Emphasis Project for Silicosis. NIOSH investigators determined that an occupational health hazard due to exposures to respirable silica and noise existed for workers at Diversified Roofing Inc. Recommendations for controlling workplace exposures include reducing or eliminating exposures by implementing engineering controls and enforcing the use of personal protective equipment under the OSHA respirator program guidelines. Employees need education regarding the potential health hazards of respirable silica exposure, and an employee monitoring program as per the OSHA Special Emphasis Program on silica should be implemented. Additional recommendations are included at the end of this report.