Special thanks to Isher Gill for his assistance in writing this advisory.
On October 19, 2026, a Northern District of Mississippi court denied the Department of Justice’s request, on behalf of the Environmental Protection Agency (EPA), to dismiss a lawsuit challenging a power plant serving a data center. Two civil rights advocacy organizations brought the suit against the plant’s developers.
The plaintiffs allege that the developers violated the Clean Air Act (CAA) by building and operating the plant’s gas-fired combustion turbines without a permit.
The court allowed the United States to intervene but rejected its argument that the CAA authorizes it to unilaterally dismiss citizen suits it believes conflict with federal interests. Instead, the court explained, the government can preclude a citizen suit only when it has already commenced and is diligently prosecuting a civil action.
The ruling preserves advocacy organizations’ ability to use environmental citizen suits to challenge data center development and operations.
The Dispute
In April 2026, the advocacy groups sued two data center companies, alleging ongoing violations of the CAA and Mississippi’s state implementation plan. They contend that the companies built and operated a power plant without the required permits or pollution controls.
The plaintiffs seek, among other remedies, an injunction barring operation of the plant “except in accordance with the [CAA].”
The CAA’s citizen suit provision authorizes citizens to sue anyone who proposes to construct or constructs a “major emitting facility” without the required permits, or who has violated an emission standard or limitation.
In July 2026, the United States filed an amended motion on behalf of the EPA’s administrator claiming a right to intervene as a plaintiff and dismiss the case. The government argued that both the Federal Rules of Civil Procedure and the CAA entitled it to intervene and then unilaterally dismiss the lawsuit.
Why Dismissal Failed
The court held that the CAA gives the EPA’s administrator an unconditional right to intervene in citizen suits and allowed the United States to intervene on the agency’s behalf. But it denied the government’s motion to dismiss.
The court rejected the government’s argument that the Federal Rules of Civil Procedure authorized dismissal. The rules allow a plaintiff to dismiss its own action, the court explained, but not another plaintiff’s action.
The Act’s Limits
The government also argued that the CAA authorized it to dismiss the plaintiffs’ suit, citing the Act’s text and structure, case law, and constitutional avoidance. The court rejected all three arguments.
The court found that Congress intended to allow citizen suits even when federal and state governments decline to enforce the CAA.
The Act allows the government to receive notice of an impending suit, intervene, and comment on proposed consent judgments. None of those provisions authorizes the government to unilaterally dismiss a citizen suit after intervening.
Instead, the court explained, the Act permits the federal government to preclude a citizen suit only when it has commenced and is diligently prosecuting a civil action. That had not happened here.
The court therefore concluded that the CAA did not grant the dismissal authority the government claimed.
Other Arguments Fall Short
The government cited cases to argue that federal enforcement priorities take precedence over citizens’ enforcement preferences. The court distinguished those cases: in each, the EPA had already acted to enforce the CAA.
Here, the EPA’s administrator had taken no enforcement action, so the cases did not support the government’s position.
The court also rejected the government’s constitutional avoidance argument because it found the CAA unambiguous. Even if the Act were ambiguous, the court added, its interpretation would not raise serious constitutional doubts.
The court concluded that the CAA does not authorize the government to unilaterally dismiss a citizen suit over the plaintiffs’ objection.
What Companies Should Know
Advocacy groups are increasingly filing CAA citizen suits against data center developers and operators. The ruling may encourage further challenges.
Data center developers should assess how the CAA and other environmental laws apply to their facilities and address noncompliance before litigation begins.
If you have any questions, or would like additional information, please contact one of the attorneys on our Environmental, Land Use & Natural Resources team.
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