The U.S. Environmental Protection Agency (EPA) published on May 12, 2017, a Federal Register notice delaying the effective date of the January 12, 2017, rule concerning Toxic Substances Control Act (TSCA) Section 8(a) reporting requirements from May 12, 2017, to August 14, 2017. EPA notes that Section 553(b)(1)(B) of the Administrative Procedure Act (APA) allows EPA to take action without providing an opportunity for notice or comment when it for good cause finds that “notice and public procedure thereon are impracticable, unnecessary, or contrary to the public interest.” APA Section 553(d)(3) allows the effective date of an action to be less than 30 days when a good cause finding is made. EPA states that because of the complex issues regarding the reporting requirements of the rule and the “immediate pendency” of the effective date of the reporting requirements, “it would be impractical to make the effective date of this extension 30 days after its publication, and it would be impractical to get public comments on an extension of the effective date of the rule.” In addition, according to EPA, the public interest is served by complete and accurate reporting under the rule, “which would be greatly facilitated by publication of the guidance.” EPA states that it therefore finds good cause to extend the effective date of the rule without notice and comment. As noted in our January 12, 2017, memorandum, “EPA Promulgates Final TSCA Reporting and Recordkeeping Rule for Nanoscale Materials,” in the final rule, EPA stated that it intended to issue guidance within six months, including guidance on the reasonably ascertainable standard, consolidating submissions, and generic chemical names. Given that reporting must be made one year from the effective date of the final rule, it is critical that EPA provides the guidance as soon as possible. This is particularly important given that the final rule applies to both manufacturers and processors, recognizing that the latter have not generally been subject to previous TSCA Section 8(a) reporting requirements.