OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at http://www.osha.govApr 06, 2017MEMORANDUM FORREGION ADMINISTRATORS FROM:DOROTHY DOUGHERTYDeputy Assistant Secretary SUBJECT:Delay of Enforcement of the Crystalline Silica Standard for Construction under 29 CFR 1926.1153The final rule on Occupational Exposure to Crystalline Silica in Construction, published on March 25, 2016, established a new Permissible Exposure Limit and contained several other ancillary provisions that apply to the construction industry. This rule was codified at 29 CFR §1926.1153 and became effective on June 23, 2016. Under the standard, all obligations were to commence on June 23, 2017 except for requirements for sample analysis in paragraph (d)(2)(v), which commence on June 23, 2018.The construction standard for crystalline silica has a number of unique features warranting development of additional guidance materials. In order to provide the opportunity to conduct additional outreach to the regulated community and to provide additional time to train compliance officers, we have decided to delay enforcement of this standard until September 23, 2017. We are currently developing educational materials for employers and enforcement guidance for your staff that will be made available shortly. Please instruct your staff to provide these materials to employers that are subject to the requirements under § 1926.1153 and to provide guidance on what steps the employers can take to ensure that they are in compliance with the new provisions when enforcement begins on September 23, 2017.