EPA published a final rule in the Federal Register on March 26, 2020 (85 FR 17244). The final rule completed the residual risk and technology review conducted for the Municipal Solid Waste (MSW) Landfills source category regulated under national emission standards for hazardous air pollutants (NESHAP), as well as added minor changes to the MSW Landfills New Source Performance Standards and Emission Guidelines and Compliance Times for MSW Landfills. In this action, EPA is finalizing technical revisions and clarifications to correct inadvertent errors and clarify wellhead monitoring requirements (63.1960(a)(4)(i) for the purpose of identifying excess air infiltration); delegation of authority to state, local or tribal agencies (63.1985(c)“emission standards”); applicability of the General Provisions to affected MSW landfills (63.10(d)(3)); and handling of monitoring data for combustion devices during periods of monitoring system breakdowns, repairs, calibration checks and adjustments (63.1975) for the NESHAP for MSW Landfills established in the March 26, 2020 final rule.