The federal Occupational and Safety Health Administration has established a revised National Emphasis Program to identify and reduce or eliminate worker exposures to respirable crystalline silica in general industry, maritime, and construction.

The NEP will target specific industries that are expected to have the highest numbers of workers exposed to silica, and focus on enforcing updated silica standards—one for general industry and maritime, and one for construction.

Respirable crystalline silica consists of small silica particles that are generated by cutting, sawing, grinding, drilling, and crushing materials such as stone, rock, concrete, brick, block, and mortar.

Inhaling the dust created during these operations can cause silicosis, an incurable lung disease, lung cancer, and chronic obstructive pulmonary disease.

The standards became effective June 2016. Construction employers were required to begin complying with them on Sept. 23, 2017, and they became effective for maritime and general industry on June 23, 2018.


Changes made to the NEP include:

  • A revised application to lower the permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter (µg/m3) as an 8-hour time-weighted average in general industry, maritime, and construction.
  • An updated list of target industries, as listed in the appendix of the NEP; from this list, area offices will develop randomized establishment lists of employers in their local jurisdiction for targeted inspections. Compliance safety and health officers will refer to current enforcement guidance for respirable crystalline silica inspection procedures.
  • A requirement that all OSHA regional and area offices comply with this NEP, but they are not required to develop and implement corresponding regional or local emphasis programs.
  • A mandate that state plans must participate because of the nationwide exposure to silica.

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

OSHA works to constantly monitor the effects of silica on workers and seeks input from industry experts on methods that effectively limit exposure to silica for certain equipment and tasks.

For more information, contact CBIA's Phillip Montgomery (860.244.1982).