![]() Samples were taken over 1-4 days from the 21 workers who volunteered to participate. Three construction contracting companies with expertise in pavement sealing participated in the study. It is recommended that all exposures to these compounds be reduced to the lowest possible levels (ACGIH, 2019). Four of the coal tar pitch PAHs do not have an acceptable airborne exposure level because they are thought to be cancer causing. Seven of the PAHs identified in coal tar pitch in this study have airborne occupational exposure limits or guidelines. However, exposure limits or guidelines currently focus on airborne PAH concentrations. The final sealant product applied by workers contains up to 35% RT-12 (McClintock et al., 2005).Įxposures to PAHs occur through ingestion, skin absorption, and inhalation. Small differences in PAH content between batches of sealant were observed in this study, but overall, they were very similar. The sealant is a mixture of RT-12, clay, water, and sand. Refined coal tar sealant is prepared immediately before application to paved surfaces. RT-12 is the product used in refined coal tar sealants. When the coal tar pitch is refined into 12 different viscosities, or thicknesses, RT-12 is the most viscous. Coal tar pitch is often separated, or refined, into a product known as refined coal tar pitch (RT-12). This residue contains several PAHs that are known or possible carcinogens, meaning they are known or suspected to cause, or increase the risk of developing cancer. It is the residue that remains after distilling crude coal tar. Workplace Exposures to Coal Tar Sealant and PAHsĬoal tar pitch is a by-product of coke plants and contains several PAHs that can cause cancer in humans (IARC, 2012). The results were recently published in the International Journal of Hygiene and Environmental Health and suggest that coal tar sealant workers are exposed to PAHs on the job at levels that may increase their risk of developing cancer. Researchers from the National Institute for Occupational Safety and Health (NIOSH) undertook the first occupational exposure assessment study for PAHs among coal-tar-based sealant workers. Several of these PAHs are known or suspected to cause, or increase the risk of developing cancer, but to date there has been no published research on workplace exposures to coal-tar-based sealant. ![]() Many polycyclic aromatic hydrocarbons (PAHs) are found in these sealants. Asbestos exposures probably would be higher on days when the work load was greater.Coal tar sealants are applied as a protective coating for paved surfaces. The author concludes that no asbestos hazard exists at this company, but notes that very little brake service activity occurred on the day of the survey. All exposures were well below OSHA standards of 2.0f/cc for asbestos, and 50, 5000, 1000, 10000, and 5000 micrograms per cubic meter for lead, zinc, copper, iron and manganese, respectively no standards were provided for chromium. Asbestos concentrations in personal breathing zone samples from the brake mechanic averaged 0.04 fibers greater than 5 microns per cubic centimeter (f/cc), and general area air samples contained 0.009 to 0.014f/cc. The number of employees was not reported. Worker exposures to asbestos (1332214) and trace metals were surveyed at Reading Brake and Alignment Service (SIC-7539) in Reading, Ohio, on March 7, 1979. Industrial Hygiene Report Asbestos at Reading Brake and Alignment Service, Reading, Ohio.
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