OSHA’s requirements for laboratory evaluation of silica exposure samples became enforceable on June 23, 2018. All other requirements for construction employers in the agency’s Respirable Crystalline Silica Standard became enforceable on September 23, 2017. If you’re using Table 1 to comply with the standard, the laboratory evaluation requirements don’t apply. However, if you’re using alternative exposure control methods to comply, you’ll need to ensure that your company is in compliance with the Methods of Sample Analysis described in Appendix A of the standard . If you have any questions about the standard, please contact Pete Chaney at firstname.lastname@example.org, or 301-990-2214.