DNREC Issues Notice of Violations to Delaware City Refinery for March Emissions Release

The Delaware City Refining Company has been issued a Notice of Violation for a 10-hour emissions incident that occurred on March 13^th. The NOV is for the unpermitted discharge of air contaminants, failure to operate a control device in accordance with the facility’s air permit and excess opacity from its fluid coking unit. This is separate from another incident that occurred from May 26^th to June 12^th which is still being investigated. The next step for the March incident is calculating penalties.

Additional information from DNREC:

For the incident that occurred on March 13, the refinery reported that a carbon monoxide boiler, which is a pollution control device for the refinery’s fluid coking unit, went offline during a routine fan swap. When that occurred, flue gas from the coking unit bypassed the carbon monoxide boiler and pollution treatment for approximately 10 hours. As a result, DNREC’s investigation following the incident determined the refinery released roughly 38,145 pounds of sulfur dioxide and 262,185 pounds of carbon monoxide without required pollution controls in place. Visible smoke was also released, which violated the permit conditions for opacity.

The first report of this incident was published the same day on the Delaware Environmental Release Notification System (DERNS) managed by DNREC. After collection and calculation of emissions data and an investigation, the NOV for the March violations was finalized by DNREC’s Division of Air Quality, and issued to the refinery May 29. The NOV is available on the Delaware Environmental Navigator, a DNREC system for the public that includes permitting, violation and other information about facilities and sites in the state.

An NOV is part of the multi-stage DNREC enforcement process that can include:

1. An initial report or notice of environmental release, which for an industrial facility can mean emissions believed to be over reportable or permitted limits
2. An environmental investigation, including collection of emissions data and investigation into cause of the incident
3. A Notice of Violation, which formally documents DNREC’s understanding of the facts, background and a description of a violation
4. A Notice of Administrative Penalty Assessment, proposing a monetary penalty based on the severity and duration of the violation.
5. A Notice of Conciliation, prescribing specific actions a facility has agreed to take to return to compliance.
6. A DNREC Secretary’s Order, requiring corrective measures to be completed by a set deadline.
7. A possible appeal by a facility of DNREC’s NOV, requirements or penalties, which by law can go to the Environmental Appeals Board and to state court.

DNREC has the responsibility in its environmental enforcement process to collect evidence, act in relation to applicable state law and regulations, and provide due process where the Department defends its decisions.

As a next step for the March incident, penalties will be calculated as required under state law, with considerations of violation severity, environmental harm, compliance history and economic benefit from noncompliance. A portion of any penalty assessed  would go to the Community Environmental Project Fund, which awards grants to nonprofit organizations in communities where violations occur for local environmental restoration and improvement.

The NOV for the March 13 refinery incident addresses issues separate from the sulfur dioxide releases reported between May 26 to June 12, 2025, but it does involve the operational failure of the same control device, the carbon monoxide boiler on the refinery’s fluid coking unit. The refinery has reported that in the most recent incident, a water-tube leak caused excess SO₂ emissions until the refinery repaired the leak and returned the boiler to routine service after almost three weeks of unpermitted emissions. DNREC is in the investigation phase for the May-June refinery incident to determine the full scope and duration of the release, and will proceed through the enforcement action steps as appropriate.