Respirable Crystalline Silica Standards (January 22, 2018) – OSHA issued two new respirable crystalline silica standards on March 25, 2016 including one for construction and the other for general industry and maritime. The standards became effective June 23, 2016. OSHA will begin enforcing most provisions of the standard for construction on September 23, 2017 and will begin enforcing most provisions of the standard for general industry and maritime on June 23, 2018. The Permissible Exposure Limit (PEL) of 100 ug/m3 has been reduced to 50 μg/m3 as an 8-hour Time Weighted Average (TWA) for all three(3) forms of respirable crystalline silica that are covered by the standard (quartz, cristobalite, and trydimite).  Furthermore, OSHA added an Action Level of 25 μg/m3 calculated as an 8-hour TWA.  Exposures at or above the action level trigger requirements for exposure assessment and medical surveillance. Please contact Jeff Elbert (Director of Compliance) at (918) 665-6575 or jelbert@aandmengineering.com if we can provide assistance in this regard.