On March 25, 2016, OSHA published a final rule which significantly reduces the permissible limits of silica dust to which workers can be exposed. The rule will take effect 90 days after publication, and will be codified at 29 CFR Parts 1910, 1915, and 1926.

Crystalline silica is a common mineral found in many naturally occurring materials that are used in a wide variety of industrial products. Sand, concrete, stone, ceramics, bricks and mortar all contain crystalline silica. When such materials are subjected to high-energy industrial operations such as cutting, sawing, grinding, crushing and drilling, very small particles — respirable crystalline silica — are released into the air. OSHA observes that inhalation of high levels of silica dust has been linked to lung disease (e.g., silicosis, lung cancer, chronic obstructive pulmonary disease) and kidney disease.

The final rule consists of two new silica standards, one applicable to general industry and maritime, and the other to the construction industry. Both standards reduce the total permissible exposure limits (PEL) by half: to 50 micrograms of silica per cubic meter of air, averaged over an eight-hour day. At an “action level” of 25 micrograms per cubic meter of air, employers must measure the amount of silica to which workers are exposed, although construction industry employers who implement certain OSHA-approved engineering and work practice controls are not required to measure airborne concentrations of respirable silica, and are not subject to the PEL.

The rule also requires employers to implement a written exposure control plan that identifies tasks involving exposure and corresponding protective measures, to offer medical exams every three years to workers exposed at or above the action level for 30 or more days per year, creates recordkeeping obligations, and provides guidance as to the appropriate use of respirators.

A broad range of industries is affected by the new rule, including construction, glass manufacturing, pottery products, structural clay products, foundries, dental laboratories, cut stone and stone products, ready-mix concrete, foundries, and oil and gas operations such as “fracking.” Concerned about the costs imposed by the new rule, particularly on small businesses, industry representatives are now considering challenges to the new standards both in the courts and through the legislative process.