The U.S. Environmental Protection Agency has expressed plans to revise its rules for New Source Review (NSR) permitting under the Clean Air Act, commonly known as preconstruction permitting.  In a September 2, 2025 guidance letter, EPA says it plans to propose and finalize revisions to the NSR regulations in 2026.  The rulemaking proposal will include revisions to the definition of “begin actual construction,” which, based on the September 2 guidance letter, will likely be consistent with the views described by EPA in its March 2020 Draft Guidance memorandum titled Interpretation of ‘Begin Actual Construction’ Under the New Source Review Preconstruction Permitting Regulations.  Although EPA does not intend to finalize the March 2020 Draft Guidance, until the rulemaking process is completed, EPA may weigh in on a case-by-case basis to explain what construction activities are allowed under the Clean Air Act prior to obtaining an NSR permit (or without such a permit).

EPA believes the guidance (and eventual rulemaking) will provide the regulated community with “flexibility to begin certain building activities that are not related to air emissions, such as installing cement pads,” before obtaining  an NSR construction permit.

By their nature, preconstruction permits are often one of the first steps to tackle in planning construction for new industrial projects and expansions or modifications of existing industrial sites, and there can be confusion regarding applicability.  According to EPA, the rulemaking will help the regulated community “understand what parts of construction need an NSR permit and what construction activities can proceed without an NSR permit,” which will “cut down on construction deadlines.”

Copies of the EPA Guidance and EPA News Release can be found here and here.