July 15, 2015
You might recall that the major rulemaking news in late 2013 was a long-awaited Notice of Proposed Rulemaking on silica in the Sept. 12 Federal Register, but no one was waiting with bated breath for the announcement. Federal OSHA sent the proposal to the Office of Management and Budget for vetting in February 2011, which took a glacial 921 days to accomplish.
The original proposal included two separate standards – one for general industry and maritime employment and one for construction. In addition, the proposal set a permissible exposure limit of 50 micrograms of respirable crystalline silica per cubic meter of air and required employers to monitor the airborne concentration of silica in the workplace unless they could prove there was no silica released above 25 micrograms per cubic meter of air.
OSHA expected a final silica rule by the end of 2016; however, the Senate Appropriations Committee approved an appropriations bill rider on June 25 that would require more study before the rule could be enacted. And to complicate matters, the House Appropriations Committee issued a report that urged OSHA to delay enforcing the silica standard until the agency addresses feasibility issues similar to those expressed in the Senate rider.
Although NIOSH notes that silicosis mortality in the U.S. has declined, silicosis deaths in young adults (ages 15 to 44 years) continue to occur. These deaths were likely caused by higher (acute) exposures than those that caused chronic silicosis in older persons. A total of 12 such deaths occurred during 2011-2013, with nine that had silicosis listed as the underlying cause of death. Acute silicosis develops in workers exposed to very high levels of crystalline silica. Symptoms may appear within a few weeks of an initial exposure. Chronic silicosis is the most common form of the disease. Workers usually don't show symptoms for 10 years or more after an initial exposure.
Among construction workers, the most severe exposures to crystalline silica result from sandblasting to remove paint and rust from stone buildings, metal bridges, tanks, and other surfaces. Other activities that may produce crystalline silica dust include jack hammering, rock and well drilling, concrete mixing and drilling, and cutting brick and concrete.
What is Oregon OSHA's permissible exposure limit for crystalline silica? Oregon OSHA's air contaminants rules for the construction industry sets the maximum amount of airborne crystalline silica dust that a worker can be exposed to during a standard work shift. The maximum amount is 100 micrograms of crystalline silica per cubic meter of air averaged over an eight-hour period.
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