Proposed Revisions to “Begin Actual Construction” Definition

Author: Roy Rakiewicz

The U.S. Environmental Protection Agency’s (U.S. EPA) proposed revisions to the definition of the term “begin actual construction” under the New Source Review (NSR) regulations were signed by the U.S. EPA administrator on May 11, 2026 and published in the Federal Register on May 13, 2026. The proposed changes include two significant revisions: a revised definition of “begin actual construction” and a new definition for “pollutant-emitting activities” under 40 CFR §§51.165, 51.166, 52.21, and 40 CFR Part 51, Appendix S. The current definition of begin actual construction has been in place since 1980 and prohibits certain construction activities on an emissions unit that are “permanent in nature” including installation of building foundations, underground piping, and related construction activities. Historically, the begin actual construction definition has, according to U.S. EPA, resulted in “…uncertainties, delays, and regulatory burdens that…do not represent the best reading or further the purpose of the Clean Air Act (CAA).” The proposed revisions, if finalized, will remove some of these restrictions and allow pre-permit construction activities of project components that do not emit air pollutants. Examples of pre-permit construction activities that would be allowed under the new definitions include site utility infrastructure, concrete pads, and certain types of buildings and related activities.

The preamble to the proposal reviews the history and basis for the current “begin actual construction” regulatory action and cites related historical agency-issued guidance memoranda and rule revisions from 1978, 1980, 1981, 1986, 1993, 1995, 1996, 2020, and 2025. Based on their review, U.S EPA concluded that, “…the CAA does not require a permit for all activities that could be considered construction, consistent with the U.S. EPA’s longstanding interpretation” and that “…the statute clearly prohibits construction of the components of a facility that emit or are a source of air pollution without a permit…” U.S. EPA also views a “best reading” of the CAA to be that “…an NSR permit is required when physical construction on a site begins on equipment or components that have characteristics that identify them as something that will emit air pollution, as distinguished from equipment or components that will not.” The proposal also clarifies that there is no language in the CAA or in its legislative history to suggest that pre-permit construction activity should be prohibited because it is costly or reflects “equity in the ground.” An important point related to pre-permit construction is that such construction may be subject to other non-NSR CAA requirements or other regulatory programs administered by U.S. EPA and others, referring to “cross-cutting” laws such as the Endangered Species Act or the National Historic Preservation Act.

U.S. EPA justifies its policy change by citing a Supreme Court decision which recognizes “…that agencies are free to change their existing policies if they acknowledge they are doing so, consider relevant factors including any serious reliance interests, and provide good reasons for the change.” Accordingly, U.S. EPA proposes to revise the definition of “begin actual construction” in the NSR regulations under 40 CFR §§51.165, 51.166, Appendix S to Part 51, and 40 CFR §52.21 to:

Begin actual construction means, in general, initiation of physical on-site construction of pollutant-emitting activities on a stationary source. This does not include the following: (1) Engineering and design planning; (2) geotechnical investigation (surface and subsurface explorations); (3) clearing vegetation, grading, surveying, soil compacting and stabilization (including associated pile driving), and excavating land (including blasting or other removal of hardrock); (4) ordering of equipment and materials; (5) storing of equipment or setting up temporary trailers to house construction management or staff and contractor personnel; (6) paving surfaces. This list is not intended to be exhaustive. With respect to a change in method of operations, this term refers to those on-site activities other than preparatory activities which mark the initiation of the change.

U.S. EPA also proposes to add a new definition of “pollutant-emitting activities” to the NSR regulations under 40 CFR §§51.165, 51.166, Appendix S to Part 51, and 40 CFR §52.21 as:

Pollutant-emitting activities, as used in 40 CFR 52.21(b)(6)(i) and (b)(11), include any equipment or component in a process or operation that emits or has the potential to emit a regulated NSR pollutant. Pollutant-emitting activities do not include the following: (1) office buildings; (2) retail stores; (3) buildings or structures designed for storage if the product or material to be stored therein is not capable of producing airborne vapors or particles; (4) concrete pads and building foundations, walls, and roofs that are not closed in on the interior side and do not have design elements (e.g., piping, ductwork, wiring, anchor bolts) specifically and uniquely configured to serve or support any equipment or component in a process or operation that emits or has the potential to emit a regulated NSR pollutant; (5) equipment or components whose sole purpose is heating ventilation and air conditioning for human workspaces or spaces within a building used to store supplies related to the habitation of the building; (6) wiring, piping, and associated support structures that supply utility services (including electrical, water, wastewater, or telecommunications) to a property site or a building on a site; (7) sealed junctions or tie-ins within one process that may serve equipment or components in another process constructed at a later time. This list is not intended to be exhaustive. For purposes of this definition, classification as pollutant-emitting is based on emissions from a process or operation after construction, not emissions of pollutants during the construction process.

The proposed definition of “begin actual construction” and the proposed new definition of “pollutant-emitting activities” provide more specific examples and, therefore, more clarity regarding the types of pre-construction activities that can be performed and the types of construction projects not related to an emitting activity that can be undertaken before an air permit is received. However, the intended “clarity” of the proposed rule introduces added risk where projects are started that ultimately rely on pollutant-emitting activities tied to the issuance of an air permit that is “at risk” of being issued or issued as originally proposed in an air permit application. For gray areas, U.S. EPA retains their ability to review proposed pre-permit construction activity on a case-by-case basis.

The proposed revisions must go through the rule-making process, which includes a 45-day public comment period that started when the proposed revisions were published in the Federal Register on May 13, 2026. The U.S. EPA is asking for specific comments regarding 11 aspects of the proposal, including:

• Unintended impacts of the proposal.
• Alternative approaches to the definitions.
• Additional preconstruction activities for exclusion.
• Specificity of the excluded activities.
• Additional industry-specific exclusions.
• Anticipated economic benefits.
• Prohibition of “equity in the ground” arguments by sources.
• Proposed revisions as required parts of state and local plans.
• State implementation plan (SIP) revision timing questions.
• Best possible CAA interpretation.
• Facilities’ reliance on the current regulation.

Due to the longstanding (since 1980) interpretive implementation of the begin actual construction definition, ALL4 anticipates pushback during the public comment period and possible litigation after a final rule is published. If the definitions of begin actual construction and pollutant-emitting activities are promulgated as proposed, they do not automatically supersede existing state level regulations or policies related to these definitions and states can implement rules more stringent than the federal requirements.

As always, ALL4 will keep a close eye on this new proposed rule and will be sure to provide an update when the rule is finalized, outlining if the proposed revised definitions are finalized as proposed or if updates are made to address public comments through the rule making process.

In the meantime, if you have a project where it is important to evaluate what activities can begin before an air permit is received, please contact Roy Rakiewicz at rrakiewicz@all4inc.com or (610) 422-1127.