By: John B King
It has long been clear that a permit is required prior to beginning actual construction of a facility that emits pollutants. However, what has not been clear and what has been the subject of much debate and interpretation over the years, is what physical activities denote or constitute the point in time when actual construction has begun.
The current regulatory definition of beginning actual construction is the “initiation of physical on-site construction activities on an emissions unit which are of a permanent nature,” which specifically includes the “installation of building supports and foundations.” An emission unit is “any part of a stationary source that emits or would have the potential to emit any regulated” pollutant.
In December 1978, EPA identified certain limited activities that would not involve the beginning of actual construction. These included such activities as planning, ordering of equipment and material, site-clearing, grading, and on-site storage of equipment and materials. In March 1986, EPA issued the three-page Reich Memorandum, which served to substantially limit the on-site activates that were not considered to constitute beginning actual construction. EPA did so by expansively interpreting the definition of ‘emission unit’ to include not only “units which emit pollutants …, but to any part of the source which emits a pollutant subject to regulation under the Clean Air Act.” As a result, “construction is prohibited on any emissions unit or on any installation designed to accommodate the emissions unit.”
In March 2020, the last year of the first Trump Administration, EPA revisited the definition of ‘begin actual construction.’ EPA criticized the interpretation of ‘emissions unit’ in the March 1986 Reich Memorandum as “not the best reading of the relevant regulatory text.” Instead, EPA focused on the phrase “on an emission unit.” An entity may “undertake physical on-site activities – including activities that may be costly, that may significantly alter the site, and/or are permanent in nature – provided that those activities do not constitute physical construction on an emissions unit.”
EPA parsed out the five “distinct criteria” in the first sentence of the definition, all of which must be met, for an entity to ‘begin actual construction.’ The key one is related to construction “on an emission unit.” Generally, the activity had to be “on” the unit that would emit pollutants. As to the ‘installation of building supports and foundations,’ an entity may begin such installation as long as the installation is not “on” an emission unit. Further, an ‘installation necessary to accommodate’ the emissions unit is not considered part of that emissions unit.
EPA provided an example of this interpretation in September 2025. An entity proposed to construct its facility in three stages, with the first involving construction of a core and shell building comprised of the foundation, steel superstructure, and external walls. It did not include any emission units. EPA agreed that the construction of this first stage was not within the definition, “provided that the construction of this core and shell of a building does not involve the physical construction on an emission unit or the laying of underground piping or construction of supports and foundations that are part of any emissions unit.” The March 1986 Reich Memorandum had “adopted an overly broad reading of the term” and the definition of ‘begin actual construction’ “does not prohibit initiation of physical on-site construction of those parts of a facility that do not qualify as an emission unit.” EPA indicated that it intended to “provide more clarity through rulemaking” as to how permitting “authorities may distinguish between emissions units and the other parts of a facility that are not an emissions unit or a part of an emissions unit.”
Following up on its declaration from September 2025, EPA has now proposed a rule that generally codifies its interpretations from March 2020 and September 2025. EPA has proposed to amend the regulatory definition of ‘begin actual construction’ and add a regulatory definition of ‘pollutant-emitting activities.’
Under the proposal, ‘begin actual construction’ “means, in general, initiation of physical on-site construction of pollutant-emitting activities on a stationary source.” The proposed definition specifically excludes, among other things, such activities as design planning, geotechnical investigation, clearing vegetation, grading, surveying, soil compacting and stabilization, and excavating land, ordering of equipment and materials, storing of equipment, or paving surfaces.
‘Pollutant-emitting activities’ are proposed to “include any equipment or component in a process or operation that emits or has the potential to emit” a regulated pollutant.” The proposed definition specifically excludes, among other things, office buildings, buildings or structures designed for storage (if the material to be stored is not capable of producing vapors or particles), and equipment whose sole purpose is heating ventilation and air conditioning for human workspaces or spaces.
Most importantly, though, it codifies the broad approach from March 2020 and September 2025 regarding a building that is not an emission unit. Pollutant-emitting activities do not include 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 that emits or has the potential to emit a regulated pollutant.
Generally, through these two proposed amendments, EPA seeks to allow construction, before obtaining a permit, of components that do not emit air pollutants, such as utility service infrastructure, concrete pads, and some types of buildings and building components. Construction of equipment or a component that could emit pollutants still requires a permit prior to construction.
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