The Occupational Safety and Health Administration (OSHA) has released its long-awaited proposed rule that sets new workplace permissible exposure limits (PELs) for respirable crystalline silica, and outlines methods to control exposure, conduct medical exams for workers with high silica exposure, train workers about silica-related hazards, and keep records related to crystalline silica amounts.  The proposal includes one exposure limit standard for general industry and maritime employment, and another for construction.

Occupational exposure to airborne silica dust occurs in operations involving cutting, sawing, drilling and crushing of concrete, brick, block and other stone products and in operations using sand products, such as in glass manufacturing, foundries and sand blasting.  The proposed rule would impose a PEL of 50 micrograms of respirable crystalline silica per cubic meter of air (μg/m3), averaged over an 8-hour day.

According to a fact sheet on the standard applicable to the construction industry, major provisions of the rule would require employers to:

• Measure the amount of silica that workers are exposed to if it may be at or above an action level of 25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an 8-hour day;
• Protect workers from respirable crystalline silica exposures above the PEL of 50 μg/m3, averaged over an 8-hour day;
• Limit workers’ access to areas where they could be exposed above the PEL;
• Use dust controls to protect workers from silica exposures above the PEL;
• Provide respirators to workers when dust controls cannot limit exposures to the PEL;
• Offer medical exams—including chest X-rays and lung function tests—every three years for workers exposed above the PEL for 30 or more days per year;
• Train workers on work operations that result in silica exposure and ways to limit exposure; and
• Keep records of workers’ silica exposure and medical exams.

The fact sheet on the standards applicable to general industry and maritime employment states that employers would be required to:

• Measure the amount of silica that workers are exposed to if it may be at or above an action level of 25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an 8-hour day;
• Protect workers from respirable crystalline silica exposures above the permissible exposure limit (PEL) of 50 μg/m3, averaged over an 8-hour day;
• Limit workers’ access to areas where they could be exposed above the PEL;
• Use dust controls to protect workers from silica exposures above the PEL;
• Provide respirators to workers when dust controls cannot limit exposures to the PEL;
• Offer medical exams—including chest X-rays and lung function tests—every three years for workers exposed above the PEL for 30 or more days per year;
• Train workers on work operations that result in silica exposure and ways to limit exposure; and
• Keep records of workers’ silica exposure and medical exams.

OSHA has created a web page devoted to crystalline silica, including information on the proposed rule.  OSHA plans to begin holding public hearings on the crystalline silica rulemaking on March 4, 2014. 

Photo credit: scibak