; Agricultural Worker Protection Standard Revisions (80 Fed. Reg. 67496 (November 2, 2015)); and (B) the final rule of the Administrator entitled Pesticides; Certification of Pesticide Applicators (82 Fed. Reg. 952 (January 4, 2017)); and (2) shall not revise or develop revisions to the rules described in subparagraphs (A) and (B) of paragraph (1). (b) Exceptions Prior to October 1, 2021, the Administrator may propose, and after a notice and public comment period of not less than 90 days, promulgate revisions to the final rule described in subsection (a)(1)(A) addressing application exclusion zones under part 170 of title 40, Code of Federal Regulations, consistent with the Federal Insecticide, Fungicide, and Rodenticide Act ( 7 U.S.C. 136 et seq.). (c) GAO report The Comptroller General of the United States shall— (1) conduct a study on the use of the designated representative, including the effect of that use on the availability of pesticide application and hazard information and worker health and safety; and (2) not later than October 1, 2021, make publically available a report describing the study under paragraph (1), including any recommendations to prevent the misuse of pesticide application and hazard information, if that misuse is identified.