A federal judge in northern Mississippi has refused to let the Justice Department end a Clean Air Act lawsuit against xAI. Judge Debra Brown's order, dated 19 October 2026, allowed the department to join the case but held that it has no power to shut down a citizen suit on its own. The ruling does not say whether xAI broke the law. It keeps open the question of whether the company's gas turbines at Southaven, Mississippi, needed federal permits.
“no ‘fairly possible’ interpretation of the Clean Air Act that would give the United States the right to unilaterally dismiss a citizen suit”
Judge Debra Brown, federal judge, in her order · earthjustice.org ↗
The NAACP and its Mississippi State Conference filed the suit on 14 April 2026, represented by the Southern Environmental Law Center and Earthjustice. The defendants are X.AI Corp., now a SpaceX subsidiary, and its energy affiliate MZX Tech. The turbines stand about a mile over the state line from the Colossus 2 data center in South Memphis, which helps power Grok. The plaintiffs say potential yearly emissions exceed 5,000 tons of nitrogen oxides, 400 tons of fine particulate matter and 47 tons of formaldehyde. Engadget adds that the judge found the plant feeding the data center is not mobile, so it cannot claim the exemption xAI argued for.
The Justice Department stepped in during June and argued that suits like this are burdensome regulation that threatens economic growth, energy independence and national security, and that permitting belongs to Mississippi. State regulators say portable turbines need no permit, and MZX Tech won a state permit in March for 41 permanent turbines that are not due to run until 2027. The plaintiffs call citizen suits an essential backstop when regulators fail, and say the court rejected a claim of unreviewable veto power.
Engadget's account differs on two points: it has xAI seeking dismissal with the department's backing, and places the data center in Memphis, Tennessee.
About xAI
xAI is an artificial intelligence company founded by Elon Musk on 9 March 2023. It released its first Grok model that November. SpaceX acquired it in an all-stock deal on 2 February 2026 that valued xAI at $250 billion.
This is not the first dispute over its turbines. After a 122-day build, its Colossus data center in Memphis went fully operational in December 2024, and environmental advocates said the gas turbines there ran without the permits they needed. The NAACP's April 2026 suit targets 27 unpermitted turbines at Southaven that power Colossus 2.
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Shortly before the ruling, the Fifth Circuit turned down the department's request to pause the proceedings. A separate NAACP motion from May, asking the court to shut the turbines during the case, is still undecided.