On August 9, 2019 EPA proposed the Prevention of Significant Deterioration (PSD) and Nonattainment New Source Review (NNSR): Project Emissions Accounting regulation to clarify and eliminate uncertainty relating to Step 1 of the New Source Review applicability process. EPA had previously issued the Project Emissions Accounting Under the New Source Review Preconstruction Program memorandum explaining that EPA interprets NSR regulations to allow emissions decreases, as well as increases, to be considered during Step 1 of the NSR applicability process as long as the decreases and increases are part of the single project being assessed. The August 2019 rule proposes revisions to the NSR regulations to codify this approach of including both increases and decreases resulting from the project. The rule also proposes to withdraw the Project Netting Proposal released in 2006. The comment period for the proposed rule closes on October 8, 2019.