OSHA lowers the permissible exposure limit for respirable silica.

OSHA issued a revised National Emphasis Program (NEP) February 5, 2020 to identify and
reduce or eliminate worker exposures to respirable crystalline silica. The NEP targets specific
industries expected to have the highest numbers of workers exposed to silica, such as
construction, and focuses on enforcement of the new silica standard covered in 29 CFR
1926.1153.  The original standard became effective June 2016 and construction employers
were required to begin complying with the standard as of September 23, 2017. Companies that
engage in construction activities that include excavating, cutting, grinding, sawing, drilling and
crushing materials such as stone, rock, concrete, brick, block and mortar are required to have a
written respirable crystalline silica program.

  • Revised application to the lower permissible exposure limit for respirable crystalline silica to 50 micrograms per cubic meter in an 8-hour time-weighted average.
  • Area offices will develop randomized establishment list of employers in their local jurisdictions for targeted inspections.
  • All OSHA regional and area offices must comply with this NEP, but they are not required to develop and implement corresponding regional or local emphasis programs.
  • OSHA will conduct 90 days of compliance assistance for stakeholders prior to beginning programmed inspections.

Additional information on the health effects from silica exposure can be found on  OSHA’s

Safety and Health Topics webpage on Crystalline Silica.