Health and Wellness, Injuries and Illness, Personnel Safety, Regulatory Developments

Crystalline Silica: OSHA Revises Its National Emphasis Program

On February 4, the Occupational Safety and Health Administration (OSHA) revised its National Emphasis Program (NEP) for enforcement of the construction, general, and maritime industry standards for respirable crystalline silica exposure. OSHA canceled the 2008 Crystalline Silica NEP in October 2017. The replacement NEP addresses enforcement of OSHA’s amended standards for respirable crystalline silica—promulgated March 25, 2016.

Silica dust at construction site

Alison Hancock /

The revised standards became effective June 23, 2016. Construction employers were required to begin complying with their standard as of September 23, 2017. General industry and maritime employers were required to begin complying with their standard as of June 23, 2018.

Changes in the replacement NEP include:

  • Revised application of the lower permissible exposure limit (PEL) for respirable crystalline silica to 50 micrograms per cubic meter (µg/m3) as an 8-hour time-weighted average (TWA) in construction, general industry, and maritime;
  • Updated list of targeted industries in the appendix of the NEP;
  • Instructions for area offices to develop randomized establishment lists of employers in their jurisdictions for targeted inspections from the updated list of targeted industries;
  • New respirable crystalline silica inspection procedures for compliance safety and health officers (CSHOs);
  • Requirements that all OSHA regional and area offices comply with the NEP but no requirement to develop and implement corresponding regional or local emphasis programs; and
  • Requirements that state plans participate in the NEP because of nationwide exposures to silica.

The former TWA PELs for respirable quartz silica were calculated based on silica content and were approximately equivalent to 100 µg/m3 for general industry and 250 µg/m3 for construction and shipyards.

OSHA will conduct 90 days of compliance assistance for stakeholders through its area offices before beginning programmed inspections for the NEP.

The targeted industries listed in the appendix to the NEP directive include support activities for oil and gas operations; electric power generation, transmission, and distribution; and dozens of manufacturing industries. The NEP includes a separate list of industries not targeted because they employ less than 2% of workers exposed to silica. However, an area office may include establishments in those industries if the office has specific data or knowledge of silica overexposures or there is an insufficient number of establishments on an office’s master list generated from the industries listed in the first appendix.

The enforcement directorate also instructed area offices to delete establishments from their programmed inspection lists if any establishments had a comprehensive or focused health inspection for respirable crystalline silica hazards within the past 3 fiscal years once the NEP has been in effect for 3 years and the inspection resulted in one of the following outcomes:

  • No serious citations were issued for violations of the applicable silica standard;
  • Serious citations were issued for violations of an applicable silica standard, but a follow-up inspection documented appropriate and effective efforts by the employer to abate the serious silica hazards cited (for example, air sampling conducted or engineering controls installed); or
  • Serious citations were issued for violations of an applicable silica standard, but the agency received abatement verification from the employer for all cited serious silica violations.

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