DNREC Demands Delaware City Refinery Install New Fenceline Air Sensors After Volatile Compound Release

Delaware City Refining Company offices in Delaware City. DNREC has demanded the refinery install fenceline monitors at the facility after a recent release of volatile organic compounds (VOCs) including butane and related compounds produced by the refinery /DNREC photo

The Delaware Department of Natural Resources and Environmental Control (DNREC) has issued an order demanding the Delaware City Refining Company (DCRC) quickly install fenceline sensors at the Delaware City refinery after the facility revealed that a recent release of butane and related compounds was significantly more extensive than initially reported. Butane and the related compounds that were released are flammable volatile organic compounds (VOCs) produced at the refinery.

The Department’s demand follows a release initially reported by the refinery through the Delaware Environmental Release Notification System (DERNS) on Thursday, Nov. 27 as having lasted for less than two hours that afternoon. The company later notified DNREC that the release occurred over approximately 19 hours, from 9 p.m. on Wednesday, Nov. 26 through 4 p.m. on Thursday, Nov. 27.

The Delaware Division of Public Health (DPH) has indicated to DNREC that – based on the information provided – there was likely no threat to public health when the release occurred and no long-term concern. Regardless, DNREC believes additional air monitoring by the refinery is needed given that the incident occurred for a significant period before refinery operators were aware of it, and that DNREC, DPH and the public had no opportunity at the time to evaluate potential impacts from the release while it continued.

Under the expedited order, DNREC demands that DCRC begin operating a real-time fenceline air sensor system 70 days after the order is issued. The system will measure VOCs at the facility’s property line, send alerts when levels rise above a set limit sharing that information with DNREC and the public. If the system detects a release above the limit, the refinery will be required to identify the source and begin corrective action. The parent company of DCRC, PBF Energy, is required to operate similar equipment at its refineries in California.

“Unfortunately, the refinery has had three significant environmental incidents this year and was not aware of this most recent release for some time,” said DNREC Secretary Greg Patterson. “While DNREC has been working toward additional community monitors, demanding that the refinery quickly install fenceline sensors is a step that we believe is now necessary. But it is not the end of our response to ensure future releases can be detected sooner and the public can see the data directly.”

DCRC could choose to appeal the fenceline sensor order to the state Environmental Appeals Board. The Delaware City refinery has also received DNREC Notices of Violation for emissions releases in March and May-June this year, with penalty assessments for these violations still pending.

Butane is an odorless, colorless gas used in aerosol sprays, lighters and some industrial work. The gas released by the refinery contained the same odorant used in natural gas so it could be detected by smell. After being contacted by DNREC, the Division of Public Health (DPH) reported there is no public health threat from this incident. When butane is released outdoors, it quickly spreads out into the air. Because it spreads out so fast outside, it does not lower oxygen levels and does not cause breathing problems, skin irritation or eye irritation for people nearby. DNREC’s Division of Air Quality modeling conducted this week indicates the release was carried east toward the Delaware River on Nov. 26 and 27 and concentrations at the property line and beyond were below occupational health exposure standards, suggesting low risk to ambient air quality in the Delaware City area.

Butane’s main safety concern is that it’s very flammable. Health problems from butane usually happen only in confined, tightly closed or poorly ventilated spaces. In those situations, large amounts can push out oxygen – but that does not happen in open air.

DNREC’s expedited action in demanding that the refinery install fenceline sensors is an initial step in a larger enforcement and rulemaking effort in response to this latest release incident. DNREC is also preparing a broader regulation, expected to be proposed in 2026, that would require expanded fenceline monitoring at refineries and other large facilities. When proposed, that rule will go through the state’s public process, including public comment and a public hearing.

State rules also require the refinery to send DNREC a detailed written report within 30 days of the incident. Once the report is received, DNREC will review it in full and may pursue additional enforcement actions.

DNREC has worked in 2025 with the support of Gov. Matt Meyer, House Speaker Melissa Minor Brown and state Senator Nicole Poore to address refinery issues and expand monitoring in the Delaware City area.

DNREC is also working to install an instrument to measure total VOCs at the department-operated monitoring station located on Route 9, downwind of the Delaware City refinery, to provide additional information.

The DNREC Order can be found on the DNREC website.

About DNREC
The Delaware Department of Natural Resources and Environmental Control protects and manages the state’s natural resources, protects public health, provides outdoor recreational opportunities and educates Delawareans about the environment.  The DNREC Division of Air Quality monitors and regulates all emissions to the air. For more information, visit the website and connect with @DelawareDNREC on YouTube, Facebook, Instagram, X (formerly known as Twitter) or LinkedIn.

Media contact: Michael Globetti, michael.globetti@delaware.gov; Nikki Lavoie, nikki.lavoie@delaware.gov 

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