Section 51.5 - How does an agency request approval?(a) For a proposed rule, the agency does not request formal approval but must:(1) Discuss, in the preamble of the proposed rule, the ways that the materials it proposes to incorporate by reference are reasonably available to interested parties or how it worked to make those materials reasonably available to interested parties; and(2) Summarize, in the preamble of the proposed rule, the material it proposes to incorporate by reference.(b) For a final rule, the agency must request formal approval. The formal request package must:(1) Send a letter that contains a written request for approval at least 20 working days before the agency intends to submit the final rule document for publication;(2) Discuss, in the preamble of the final rule, the ways that the materials it incorporates by reference are reasonably available to interested parties and how interested parties can obtain the materials;(3) Summarize, in the preamble of the final rule, the material it incorporates by reference;(4) Send a copy of the final rule document that uses the proper language of incorporation with the written request (See § 51.9 ) ; and(5) Ensure that a copy of the incorporated material is on file at the Office of the Federal Register.(c) Agencies may consult with the Office of the Federal Register at any time with respect to the requirements of this part. 79 FR 66278 , Nov. 7, 2014