According to a study from the Department of Public Health at the University of Massachusetts Lowell, workers at demolition, crushing, and bridge repair sites in the Massachusetts area were sometimes exposed to as much as 10 times the permissible exposure limit (PEL) of silica dust. The bridge repair site had the highest levels at 527 micrograms per cubic meter of air, while workers operating crushing machine tenders had an exposure of 93.3 micrograms, and operating engineers averaged 17 micrograms per cubic meter of air. OSHA's silica regulation established a PEL limit of 50 micrograms per cubic meter.
Controlling or reducing silica exposure below OSHA’s PEL “remains challenging for chipping workers and crushing machine tenders. Even with the use of dust suppression controls, respiratory protection may be required for various tasks,” the researchers said. They recommend that employers provide additional respiratory safeguards for these workers.Read More