On March 14, 2025, the District of Columbia Department of Energy and the Environment (DOEE) proposed to renew and revise the existing source category permits for diesel-fired and natural gas-fired emergency engines. These revised source category permits apply to engines that are exempt from the federal New Source Performance Standards (NSPS) but are still subject to the National Emission Standards for Hazardous Air Pollutants (NESHAP) Subpart ZZZZ (commonly referred to as the “RICE MACT”. The proposed updated permits are Permit Nos. 7115-SC-R2 for diesel-fired engines and 7116-SC-R2 for natural gas-fired engines. These revisions are intended to renew and update the current source category permits, which are set to expire on September 29, 2025.
Owners and operators of diesel-fired emergency engines must apply for coverage under Permit 7115-SC-R2 if their engines are exempt from NSPS Subpart IIII but still subject to NESHAP Subpart ZZZZ. Similarly, owners and operators of natural gas-fired emergency engines will need to seek coverage under Permit 7116-SC-R2 if their engines are exempt from NSPS Subpart JJJJ but are subject to NESHAP Subpart ZZZZ. The revised permits would be valid for 5 years from the issuance date.
While the applicability of the source category permits remains unchanged. The permits have both been updated to reflect changes to DC regulations since the prior permits were issued, specifically for opacity regulations (20 DCMR 606) and odor regulations (20 DCMR 903), which became effective in August 2023.
Once the new permits are issued, no new applications for coverage under the old permits will be accepted. Any applications for new engines will need to use the new forms, and coverage will be granted under the updated permits. Operators with engines currently covered under one of the existing source category permits must submit a renewal application by June 26, 2024. For both new and existing generators, the permit application fee is $500 or $1,000, depending on the size of the engine. DOEE will issue invoices upon application submission, and the 45-day approval clock for the source category permit begins once payment is received.
The draft application forms and permits (available for review and comment) can be found below:
- Permits and Application Forms
- Public Notices
Public comments can be submitted until April 13, 2025. If you need assistance in determining if these source category permits could apply to your operations or would like assistance in reviewing the revised source category permits, please contact Trinity’s DC office at 240.379.7490
