The 10th U.S. Circuit Court of Appeals revived a citizen lawsuit challenging repeated pollution at Suncor's Commerce City refinery and sent the case back to the trial court for closer review. The appellate panel questioned whether Colorado and EPA enforcement actions — including settlements and consent decrees — imposed meaningful consequences. Plaintiffs say North Denver and nearby low-income neighborhoods continue to suffer chronic contamination, and the trial court will now decide whether regulators' responses were sufficient.
Appeals Court Revives Lawsuit Letting Colorado Residents Sue Suncor Over Refinery Pollution
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An appeals-court decision has revived a lawsuit challenging repeated air pollution from Suncor's refinery in Commerce City, Colorado, allowing environmental groups and nearby residents to continue pressing claims tied to state and federal enforcement actions.
What the Court Ruled
The 10th U.S. Circuit Court of Appeals reversed a 2024 dismissal and sent the case back to the federal trial court in Denver. The appeals panel instructed the lower court to take a closer look at whether Colorado and EPA enforcement — including penalties, settlements and consent decrees — were actually diligent and consequential enough to bar outside citizen suits.
The appellate court found the district court "appeared to lump together and weigh equally all the administrative actions taken by EPA and Colorado, even the ones that imposed no consequences on Suncor."
Background
A coalition of citizen-plaintiffs, including Earthjustice, Colorado GreenLatinos, the Sierra Club and local residents, had sued Suncor over alleged, repeated violations at its Commerce City refinery. In 2024 a federal judge dismissed the suit after finding Colorado's settlements and consent decrees showed the state was already enforcing air laws and thus left no role for citizen enforcement.
Suncor attorney Hugh Gottschalk urged deference to agencies, arguing the court should respect the regulators' discretion in addressing emissions. Suncor did not immediately comment publicly after the appeals ruling.
Why It Matters
The case could set an important precedent about whether communities can go to court when regulators choose negotiated remedies rather than more punitive actions. Plaintiffs say North Denver and adjacent lower-income neighborhoods have endured chronic contamination and that fines and settlements to date have been too small to produce lasting reductions in pollution.
Margaret Kran-Annexstein, director of Colorado Sierra Club: "For decades Suncor has delivered extraordinary levels of toxic pollution to North Denver and been fined pennies."
GreenLatinos vice president for state programs Ean Tafoya called the decision "deeply personal," and added that "when decision-makers fail to enforce the law, we must be able to fight back."
The next step is for the trial court to review the enforcement record and determine whether the administrative actions taken by state and federal regulators meaningfully differ from the relief the citizen groups ask the court to require. Until that review is complete, the broader lawsuit remains active and the underlying dispute unresolved.
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