Proposed Revisions to Minor New Source Review Public Participation Requirements

Author: Roy Rakiewicz

On July 7, 2026, The U.S. Environmental Protection Agency (U.S. EPA) proposed to revise the public participation regulatory requirements for sources subject to Clean Air Act (CAA) minor new source review (NSR) programs approved into State Implementation Plans (SIPs). Minor NSR programs apply to minor stationary sources, minor modifications to existing stationary sources, and include synthetic minor sources and modifications. Minor NSR programs can also include general permits and permits by rule that, “…describe preconstruction authorization mechanisms that apply standardized eligibility criteria and pollution control requirements to categories of similar new and modified sources of air pollution.”

U.S. EPA proposes to revise 40 CFR §51.161, which specifies the public participation requirements for state and local minor new source review programs. Under 40 CFR §51.161(b) an “opportunity for public comment” on the new construction or modification of any stationary source includes:

“(1)Availability for public inspection in at least one location in the area affected of the information submitted by the owner or operator and of the State or local [air] agency’s analysis of the effect on air quality, (2) A 30-day period for submittal of public comment, and (3) A notice by prominent advertisement in the area affected of the location of the source information and analysis specified in paragraph (b)(1) of this section.’’

The underlying statutory requirement for minor NSR SIPs is CAA section 110(a)(2)(C), which provides the basis for minor NSR programs for “…regulation of the modification and construction of any stationary source within the areas covered by the plan and as necessary to assure that the national ambient air quality standards are achieved…” U.S. EPA points out that the statutory language does not specify what regulatory agencies must include in their SIPs to be approvable by U.S. EPA, and notes that CAA section 110(a)(2)(C) does not even “prescribe” the use of permits to authorize minor sources and minor modifications, thereby providing regulatory agencies broad discretion for their minor NSR programs.

Further justification is provided for the proposed revisions to 40 CFR §51.161 through the observation that “… U.S. EPA’s general regulatory requirements for preconstruction review programs at 40 CFR 51.160 – 51.164 have not kept pace with statutory amendments made after the initial promulgation of these regulations” because they are generally unchanged since 1973 and “…do not distinguish between ‘‘major’’ new sources and modifications and ‘‘minor’’ new sources and modifications.” U.S. EPA further surmises that these requirements, initially adopted as a result of a court order, were approved to ensure NAAQS compliance with a focus at that time on “…the most heavily polluting sources.” The major NSR program  provisions established in the 1977 CAA amendments  included requirements for major sources with greater air quality impacts and left regulatory agencies with discretion for regulating minor sources, “as necessary,” to achieve the NAAQS.  The provisions of 40 CFR §51.160 – §51.161 are characterized by U.S  EPA as “…part of a historical remnant…” in the proposal and thus “… remained the only regulations governing minor sources and modifications” following the promulgation of the major NSR requirements in 1977.

Consistent with other recent regulatory revisions, U.S. EPA provides a “best reading” of CAA under Loper Bright v. Raimondo¹, of CAA section 110(a)(2)(C), which states that it “… delegates discretionary authority to the U.S. EPA with regard to determining whether a State or local air agency’s program for regulating stationary source construction and modification that is not subject to the major source requirements in parts C and D of title I of the CAA is sufficient to assure maintenance and attainment of the NAAQS.” U.S. EPA concludes that because of the lack of specificity in the statute and its inclusion of the phrase “as necessary,” CAA section 110(a)(2)(C) is “…best read to limit the U.S. EPA’s authority to impose specific regulatory requirements in determining what is ‘‘necessary’’ for a minor NSR program to satisfy statutory requirements such that it is approvable…”. With regard to public participation, U.S. EPA states “[t]here is no explicit requirement for public participation in preconstruction review of minor sources in CAA section 110(a)(2)(C)” and U.S, EPA proposes to allow regulatory agencies to decide how much, if any, public participation to include in their minor NSR programs.

Translation

U.S. EPA is proposing revisions to 40 CFR §51.161 that will remove the minor NSR public participation requirements for SIPs. Should the revisions be finalized as proposed, regulatory agencies will be authorized to revise their SIPs to reflect the revised requirements under 40 CFR §51.161, which could include modifying or removing existing minor NSR public participation requirements. The proposed revisions of 40 CFR §51.161 do not reflect mandatory SIP requirements and regulatory agencies are not required to revise their SIPs as a result of the proposed revisions. However, should a regulatory agency wish to revise their minor NSR public participation SIP requirements in accordance with revisions to 40 CFR §51.161, they would need to use the SIP revision process, which includes developing a SIP submittal including the proposed revisions, after providing both reasonable notice and public hearings on a draft version of the SIP document and submittal to U.S. EPA for review and approval.

Impacts

Should the revisions be finalized as proposed, regulatory agencies could decide to revise or remove the public participation provisions of their minor NSR programs.  Such changes would require SIP revisions (after notice and comment) reflecting the regulatory agency’s  intent  to revise or eliminate their minor NSR public participation requirements.  The  primary impact of reduced minor NSR program  public participation requirements would  be reflected in a reduction of the time needed  to obtain a minor NSR construction permit because the mandatory public review period (typically 30 days), and the obligation of the regulatory agency to address public comments before finalizing a minor NSR permit in those jurisdictions, would be reduced or eliminated.

The impacts of U.S. EPA’s proposal will not be immediate. Regulatory revisions take time and even if this proposal is finalized, regulatory agencies will be obligated to prepare SIP revisions, which are subject to public notice and comment requirements and U.S. EPA review and approval. Therefore, any minor NSR permit timeline relief associated with the proposal is likely 18 months or more away.

U.S. EPA notes in the proposal that for Title V facilities, the terms and conditions of minor NSR permits for modifications would be subject to review and comment during reopenings and renewals of associated Title V permits. U.S. EPA also makes it very clear that regulatory agencies are not obligated to revise their SIPs should the proposal be finalized. There is a strong likelihood that proposed SIP revisions aimed at limiting minor NSR public notice requirements will be opposed in many jurisdictions, especially in areas where state and local environmental justice (EJ) and related state-only rules and policies routinely generate public interest.

Conclusions

The proposal, if finalized, will provide permit timeline relief in areas where the regulatory agency has prepared, published, and obtains U.S. EPA approval for their minor NSR SIP revision, which would revise or remove public participation requirements for their minor NSR program. The proposed revisions to 40 CFR §51.161, if finalized, will not   result in mandatory SIP revisions and not all regulatory agencies will revise their minor NSR programs. Proposed SIP revisions reflecting reduced minor NSR public participation may encounter public opposition. The proposal was published on July 7, 2026 and the public comment period ends on August 21, 2026. ALL4 routinely assists clients prepare public comments in response to regulatory proposal. Please contact your ALL4 Client Manager or Roy Rakiewicz if you have any questions or wish to provide comments in response to this proposal.

¹ 603 U.S. 369 (2024)