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OSHA Revises Silica Standards

April 15, 2016
Final rule introduces new exposure limits to respirable crystalline silica

On March 25, 2016, the U.S. Occupational Safety and Health Administration (OSHA) issued its long-awaited revised standards for occupational exposure to respirable crystalline silica (81 Fed. Reg. 16286). OSHA issued two separate standards — one for general industry and maritime, and the other for the construction industry — to tailor requirements to the unique circumstances found in these sectors. The rule impacts more than 2.3-million American workers across a wide spectrum of industries, according to OSHA, and is expected to save the lives of more than 600 workers per year. Its implementation will likely have broad logistical and cost implications for many employers in numerous industry sectors. This article provides highlights of the final rule.



OSHA determined that employees exposed to respirable crystalline silica at the previous permissible exposure limits (PEL) set in 1971 face a “significant risk” of material impairment to their health. According to OSHA, evidence indicates workers exposed to respirable crystalline silica are at increased risk of developing silicosis and other non-malignant respiratory diseases, lung cancer and kidney disease. The previous standards were issued over four decades ago; much more now is known about respirable crystalline silica and exposure to it in the workplace.

Final Rule

The final rule establishes a new PEL of 50 micrograms of respirable crystalline silica per cubic meter of air (50 μg/m3) as an 8-hour time-weighted average (down from 100 μg/m3) allowed for general industry, and reduces the amount allowed for the construction and maritime industries from 250 μg/m3 to 50 μg/m3. OSHA believes these new limits are “the lowest level feasible for all affected industries.”

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The final rule also includes provisions to protect employees, such as requirements for exposure assessments, methods for controlling exposure, respiratory protection, medical surveillance, hazard communication and recordkeeping. The mandates vary between the general and maritime industries and the construction industry. Provisions pertinent to the general and maritime industries include requirements to: supply respirators to workers to control silica exposures above the PEL where engineering control measures can’t do so; give medical exams every three years to workers exposed at or above the action level of 25 μg/m3 for 30 or more days a year; provide additional training and monitoring; and abate housekeeping practices that may expose workers to silica if alternative practices are available.

Provisions pertinent to the construction industry include requirements to develop a written exposure plan to control exposures to areas where higher exposures can be expected; provide medical exams every three years for workers exposed at or above the action level of 25 μg/m3 for 30 or more days a year; implement dust control measures to protect workers exposed to silica above the PEL where feasible alternatives practices are available; and perform additional recordkeeping.

The final rule also includes medical surveillance for employees in the general and maritime industries who are exposed above the PEL for 30 or more days a year, beginning on June 23, 2018, and to workers who will be exposed at or above the action level for 30 or more days per year beginning on June 23, 2020.


OSHA has worked long and hard on updating these 40-year-old-plus standards for crystalline silica. The new standards will have significant implications for many industries. Not everyone is happy. Some in the construction industry have expressed concern about the capacity of current air-filtration and dust-removal technologies and the feasibility of such technologies to achieve these more-stringent standards. Others have stated the current exposure limits are protective when adhered to and enforced, and question the need for more-stringent standards. How these issues play out remains to be seen. What is clear is that the new standards are here to stay unless judicially challenged and a court thinks otherwise.

LYNN BERGESON is Chemical Processing's Regulatory Editor. You can e-mail her at [email protected]Lynn is managing director of Bergeson & Campbell, P.C., a Washington, D.C.-based law firm that concentrates on conventional, biobased, and nanoscale chemical industry issues. She served as chair of the American Bar Association Section of Environment, Energy, and Resources (2005-2006).

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