The U.S. Environmental Protection Agency on Sept. 9 announced the availability of new guidance on New Source Review (NSR) preconstruction permitting requirements.
The EPA guidance, dated September 2, 2025, is a site-specific determination regarding TSMC Arizona Corporation’s (TSMC) construction of a semiconductor manufacturing facility core and shell building that does not involve any emissions units (the TSMC Guidance).
EPA finds that the permit applicant can begin construction on this building before obtaining a pre-construction permit, with certain limitations. However, the permitting authority, Maricopa County Air Quality Department (MCAQD), has the ultimate discretion to make the decision.
Under current NSR regulations, a facility owner or operator is prohibited from initiating “actual construction” until an air permit has been issued.
This term refers specifically to the start of permanent, on-site construction activities on emissions units—such as installing foundations, supports, or pipework.
In line with a 2020 draft guidance that was never finalized, EPA is now updating its interpretation to allow construction to begin on portions of a facility that do not qualify as emissions units.
EPA has authorized TSMC Arizona Corporation to begin pouring foundations and constructing the core and shell of a semiconductor plant, provided no work is done on equipment that constitutes an emissions unit.
This marks a departure from previous EPA policy, which limited pre-permit activities to actions like site clearing, grading, equipment ordering, and temporary storage.
APPA said the TSMC Guidance reveals the present Administration’s more flexible views on “begin actual construction” that may be advantageous to a utility building new generation or modifying an existing facility.
Importantly, the permitting authority makes the final decision regarding what activities can be conducted before the permit is issued.
As a result, the TSMC Guidance may prove to be helpful to utilities constructing in pro-industry states. These agencies may be more likely to allow more pre-construction activities, knowing EPA supports a less onerous interpretation of “begin actual construction.” The TSMC Guidance may also be read as an invitation for more applicability determinations until EPA can complete a forthcoming rulemaking.
The Spring 2025 Unified Agenda abstract for this future rulemaking, entitled Revision to “Begin Actual Construction” in the New Source Review Preconstruction Permitting Program, purports to provide “additional flexibility” for case-by-case determinations of what constitutes actual construction before a pre-construction permit is obtained.
