In this action, the U.S. Environmental Protection Agency (EPA) is finalizing technical revisions and clarifications for the national emission standards for hazardous air pollutants (NESHAP) for MSW Landfills established in the March 26, 2020, final rule. This final rule also amends the MSW Landfills NSPS at 40 CFR part 60, subpart XXX, to clarify and align the timing of compliance for certain requirements involving installation of a gas collection and control system (GCCS) under related MSW landfill rules. Additionally, the EPA is revising the definition of Administrator in the MSW Landfills Federal Plan that was promulgated on May 21, 2021 to clarify who has the authority to implement and enforce the applicable requirements. The EPA is also making some minor typographical corrections.