The Division of Air Quality will conduct a public hearing (Docket #2025-R-A-0015) on a proposed State Implementation Plan (SIP) revision. Public comment period open through Oct. 7, 2026.

On June 4, 2018, the Environmental Protection Agency (EPA) designated 51 areas of the country as “non-attainment” under the 2015 8-hour ozone National Ambient Air Quality Standard (NAAQS) of 0.070 parts per million. Ground level ozone, one of the principal components of smog, is a serious air pollutant that harms human health and the environment. Among those non-attainment areas was the Philadelphia-Wilmington-Atlantic City (PA-NJ-MD-DE) Moderate Non-Attainment Area (Philadelphia NAA). This NAA included New Castle County in Delaware.

On October 7, 2022, the EPA published a final rule to reclassify certain ozone nonattainment areas from Marginal to Moderate for the 2015 ozone NAAQS. Under the Moderate non-attainment classification, the Philadelphia NAA did not meet the standard by the deadline of August 3, 2024.

On July 30, 2024, the EPA published a final rule to reclassify the Philadelphia NAA as Serious for the 2015 8-hour ozone NAAQS, with a new attainment date of August 3, 2027, and instructed states in the NAA to develop non-attainment plans. Subsequently, on June 4, 2026, the EPA issued a final rule creating a stand-alone NAA for New Castle County, Delaware; removing Delaware from the Philadelphia NAA. This hearing will address Delaware’s Serious Non-attainment Plan for New Castle County for the 2015 8-Hour Ozone NAAQS.

For additional information and to view the proposed SIP revisions visit the Delaware Register of Regulations, beginning Sept. 1, 2026. For more information, or to view the proposed SIP revisions in person, by appointment-only, contact Kelsey Schiliro, at the DNREC Division of Air Quality, 715 Grantham Lane, New Castle, Delaware, 19720, or via phone 302-323-4542 or by email at Kelsey.Schiliro@delaware.gov.

The Department will accept public comment through Oct. 7, 2026. Comments will be accepted in written form via email to DNRECHearingComments@delaware.gov, using the online form at de.gov/dnreccomments, or by U.S. mail to the address on this page.

Public Hearing Officer: Theresa Smith
DNREC Office of the Secretary
89 Kings Highway
Dover, DE 19901

Proposed DNREC Exhibits

Exhibit 1: Environmental Protection Agency’s Final Rule. 2015 Ozone NAAQS, Designation of Areas for Air Quality Planning Purposes, Reclassification to Serious.

Exhibit 2: Environmental Protection Agency’s Final Rule. 107 Clean Air Act Redesignation and Clean Data Determinations.

Exhibit 3: Delaware’s State Implementation Plan “Moderate Non-Attainment Plan for New Castle County for the 2015 8-Hour Ozone National Ambient Air Quality Standard,” as submitted to EPA on March 4, 2024.

Exhibit 4: Register Notice for the proposed revision to Delaware’s State Implementation Plan “Proposed Revision to Delaware State Implementation Plan Revision Serious Classification Requirements for New Castle County for the 2015 8-Hour Ozone National Ambient Air Quality Standard,” published in Delaware Register of Regulations on September 1, 2026.

Exhibit 5: Affidavit and legal notice in the August 12, 2026, Delaware State News.

Exhibit 6: Affidavit and legal notice in the August 12, 2026, News Journal.

Exhibit 7: Hearing notice on the State of Delaware Public Meeting Calendar, August 17, 2026.

Exhibit 8: Legal notice as posted on the website for DNREC Public Notices, dated August 12, 2026.

Exhibit 9: “Proposed Delaware State Implementation Plan Revision for Serious Classification Requirements for New Castle County for the 2015 8-Hour Ozone National Ambient Air Quality Standard,” as published in the September 1, 2026, Delaware Register.

Exhibit 10: DNREC Presentation