On May 30, 2025, the U.S. Environmental Protection Agency (EPA) closed the public comment period for its proposed rule titled “Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Large Municipal Waste Combustors Voluntary Remand Response and 5-Year Review; Reopening of Comment Period”. The proposed amendments include a comprehensive revision of emissions limits and regulatory requirements for large municipal waste combustors (MWCs), including both new and existing waste-to-energy (WTE) facilities.
These changes reflect EPA’s reevaluation of the maximum achievable control technology (MACT) floor levels following a voluntary remand and a petition for reconsideration, as well as the agency’s 5-year review obligation under the Clean Air Act. The rule also proposes the elimination of startup, shutdown, and malfunction (SSM) exemptions, updates to electronic reporting requirements, corrections to technical and typographical errors, and clarification of provisions related to air curtain incinerators and applicability dates.
As part of the public record, the Earth Engineering Center at The City College of New York (CUNY) submitted a technical analysis during the initial comment period, which closed in March 2024. This study, titled “Technical Assessment of Current APC Performance to Theoretical Emissions Reductions”, was commissioned by the American Society of Mechanical Engineers (ASME) Material and Energy Recovery (MER) Division. It evaluates the performance of air pollution control (APC) systems currently employed at WTE facilities in the U.S. and Canada. The assessment is accompanied by a preliminary health risk analysis to contextualize measured emissions in terms of potential community exposure and health impacts. The findings in the technical assessment are consistent with the objective of EPA to ensure facilities achieve emission levels below Federal and State permit limits.
Earlier Engagement on Transparency and Cost Methodology (2023)
The 2024 submission builds on earlier engagement by the EEC. In May 2023, EEC submitted a comment to the EPA’s non-rulemaking docket, Reviewing Emission Standards for Clean Air Act section 129 pollutants from the Large Municipal Waste Combustor source category, opened to solicit stakeholder input ahead of formal rulemaking. In that comment, EEC requested that the Agency make public the data and modeling assumptions used to develop its preliminary cost projections for emissions control technologies, which were referenced in presentations shared with stakeholders. This submission was spearheaded by EEC researcher Erica Razook.
The comment noted that the EPA’s initial materials outlining potential cost implications for municipal facilities lacked sufficient detail for meaningful technical evaluation. EEC emphasized that transparency in cost methodology is critical to ensuring that any future regulatory requirements are grounded in feasibility and informed by the most up-to-date research in emissions control.