The Delaware Department of Natural Resources and Environmental Control (DNREC) recently finalized updates to four state air quality regulations to revise requirements related to startup, shutdown, and malfunction (SSM) events. In June 2015, the United States Environmental Protection Agency (EPA) issued a final rule known as the 2015 SSM SIP Call which required 36 states (including Delaware) to remove exemptions from SSM events in their state rules. In November 2016, DNREC finalized revised regulations to address the 2015 SSM SIP Call. However, in October 2023, EPA disapproved Delaware’s State Implementation Plan (SIP) revision and determined that the revised regulations did not fully resolve the deficiencies identified in the 2015 SSM SIP Call.
In order to address EPA’s October 2023 disapproval, DNREC finalized updates to four air quality regulations. The regulations were finalized January 7, 2025 and were effective February 11, 2025. The following provides a summary of the revisions to each regulation:
- Regulation 1104 Particulate Emissions from Fuel Burning Equipment – Removed the 30-day rolling average requirement which previously applied during SSM events. The particulate matter emission standard of 0.3 lb/MMBtu (maximum two-hour average) now applies at all times.
- Regulation 1105 Particulate Emissions from Industrial Process Operations – Removed the 30-day rolling average requirement which previously applied during SSM events. The particulate matter emission standard of 0.2 gr/scf now applies at all times.
- Regulation 1109 Emissions of Sulfur Compounds from Industrial Operations – This regulation applies only to sulfuric acid manufacturing and sulfur recovery units. DNREC removed the SSM exemption in this rule.
- Regulation 1114 Visible Emissions – DNREC removed the SSM exemption in this rule and added a new requirement that during startup and shutdown event visible emissions cannot be greater than 40% opacity for more than 6 consecutive minutes in any 1-hour period.
If you would like to discuss the Delaware air regulation updates and how they may impact your facility, please contact Christie Heath in Trinity’s Philadelphia office or call 610.472.8349.
