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Tightening Silica Exposure Standards

Client Alert

Author: Gregory S. Narsh

Tightening Silica Exposure Standards

On June 23, the Occupational Safety and Health Administration (OSHA) implemented one of the final legs of a new rule limiting worker exposure to crystalline silica (or simply “silica”). Exposure limits and protective measures before the new rule were based on studies that were performed as long ago as the 1960s, and that OSHA believed to be outdated. The new rule significantly lowers the silica level that workers may be exposed to and imposes several additional requirements on employers. Compliance with the rule will present challenges for some employers and industries at a time when OSHA enforcement and OSHA penalties have been on the rise.

Most in the regulated community are aware of the increasingly strict regulation of asbestos and asbestos-containing material (ACM) that began in the 1970s. The U.S. EPA has placed restrictions on manufacturing, importing and using these materials. OSHA also has heavily regulated worker exposure to ACMs. While ACMs are not “banned,” as many believe, their use is restricted. Recently, the attention of agencies like EPA and OSHA, as well as workers and even the general public, has been focused on silica in much the same way as asbestos.

Crystalline silica is a common mineral that is found in materials such as stone, artificial stone and sand. When workers cut, grind or drill materials that contain crystalline silica, or use industrial sand, they can be exposed to very small silica dust particles. These particles (known as “respirable” particles) can enter an unprotected worker’s lungs and cause silicosis, an incurable and sometimes deadly lung disease. Respirable crystalline silica can also cause lung cancer, chronic obstructive pulmonary disease, and even kidney disease. In most cases, these diseases occur after years of exposure to respirable crystalline silica.1

Like asbestos before it, the use of silica is not banned, but additional restrictions are being imposed. For many individual chemicals or substances, OSHA has established maximum permissible exposure levels (PELs). These exposure restrictions may be based on instantaneous exposure, short-term exposure or exposure that is averaged over an eight-hour work period. Only a few substances have a separate section of the OSHA regulations dedicated to them. Crystalline silica is one, regulated at 29 CFR 1910.1053.2

Before implementation of the new rule, the PELs for general industry and the construction industry were 100 micrograms per cubic meter (ug/m3) and 250 ug/m3, respectively. The new rule changes the PEL to 50 ug/m3 for all industries. The rule, promulgated in March 2016, took effect for the construction industry on June 23, 2017 and for general industry on June 23, 2018.3

In addition to lowering the PEL for crystalline silica, the new rule will also require that employers:

  • Determine the amount of silica that workers are exposed to if the amount is, or may reasonably be expected to be, at or above the action level of 25 μg/m3 (micrograms of silica per cubic meter of air), averaged over an eight-hour day

  • Protect workers from respirable crystalline silica exposures above the PEL of 50 μg/m3, averaged over an eight-hour day

  • Limit access to areas where workers could be exposed above the PEL

  • Use dust controls and safer work methods to protect workers from silica exposures above the PEL

  • Provide respirators to workers when dust controls and safer work methods cannot limit exposures to the PEL

  • Establish and implement a written exposure control plan that identifies tasks that involve exposure and methods used to protect workers

  • Restrict housekeeping practices that expose workers to silica, such as using compressed air without a ventilation system to capture dust and dry sweeping, where effective, safe alternatives are available

  • Offer medical exams — including chest X-rays and lung-function tests — every three years to workers exposed at or above the action level for 30 or more days per year

  • Train workers on the health effects of silica exposure, workplace tasks that can expose them to silica, and ways to limit exposure

  • Keep records of workers’ silica exposure and medical exams.

The “hierarchy” of remedies generally preferred by OSHA include (1) eliminating a hazard, if possible; (2) if the hazard cannot be eliminated, providing engineering solutions that reduce the hazard; and (3) when still necessary to reduce exposure below the PEL, providing appropriate personal protective equipment. The new rule will challenge employers to reduce worker exposure in ways that are protective of the worker, compliant with the law, and economical.

States that implement their own OSHA programs (approximately half the states) had six months to adopt a rule that was at least as strict as the federal rule. States can impose additional restrictions, as long as they are not inconsistent with federal law. Michigan has adopted the content and timing of the federal rule.4


1 See generally “OSHA Fact Sheet,” https://www.osha.gov/Publications/OSHA3682.pdf.

2 Among several others are asbestos, vinyl chloride, chromium (VI) and benzene.

3 There are certain exceptions; for example, engineering controls in the hydraulic fracturing industry are exempt until June 23, 2021.

4 See https://www.michigan.gov/documents/lara/lara_miosha_part590_553335_7.pdf.

The material in this publication was created as of the date set forth above and is based on laws, court decisions, administrative rulings and congressional materials that existed at that time, and should not be construed as legal advice or legal opinions on specific facts. The information in this publication is not intended to create, and the transmission and receipt of it does not constitute, a lawyer-client relationship.

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