EPA Proposes New Rule Clarifying “Begin Actual Construction” Under Clean Air Act NSR Program

On May 13, 2026, the U.S. Environmental Protection Agency (EPA) published its highly anticipated Proposed Rule, “Begin Actual Construction in the New Source Review (NSR) Preconstruction Permitting Program” (91 Fed Reg 26958), kicking off the formal rulemaking process to reshape the Clean Air Act’s (CAA) NSR preconstruction permitting program, principally, by redefining the term “begin actual construction” (hereafter, the “Proposed Rule”).

The Proposed Rule distinguishes between the construction of a stationary source and the construction of non-emitting components or structures and clarifies that the latter can occur before obtaining an NSR permit. At a critical moment when power plants are expanding, data centers are proliferating, and electricity demand is spiking across the country, the Proposed Rule provides companies greater flexibility to commence physical onsite construction of non-emitting components and structures prior to obtaining an NSR permit.