The U.S. Department of Justice has formally aligned with xAI in a legal challenge aimed at halting the company’s operation of dozens of unpermitted natural gas turbines near its Memphis data centers, as reported by Wired. In a memorandum filed on Monday, the DoJ argued that if the NAACP—which initiated the lawsuit in April—wins, it would jeopardize “American national, economic, and energy security by seeking to shut off the power supply for artificial-intelligence innovation that supports the Department of War’s military operations.”

According to the Justice Department’s filing, xAI’s Grok model is one of four AI systems supporting “mission-critical operations,” including recent military strikes in Iran. The NAACP first signaled its intent to sue xAI last June, demanding an end to the company’s use of “mobile” gas turbines at its Colossus and Colossus 2 data centers. Those efforts proved unsuccessful, and Elon Musk’s AI firm has since expanded its turbine fleet to 57 units. Because the turbines remain mounted on trailers, xAI claims they are exempt from Mississippi air pollution regulations for one year. However, the Southern Environmental Law Center—representing the NAACP in the lawsuit—counters that this practice violates federal law, which treats trailer-mounted turbines as stationary equipment subject to regulation.

The NAACP has highlighted that the Memphis region, already one of the most polluted in the country, has experienced worsening air quality since xAI’s data centers began operations. Since last year, the number of turbines at these facilities has more than doubled, leading to a corresponding rise in three major air pollutants: PM2.5, formaldehyde, and oxides of nitrogen (NOx). All three are linked to asthma and cardiovascular disease; formaldehyde exposure increases cancer risk, while PM2.5 has been associated with conditions ranging from stroke to Alzheimer’s disease.

xAI, now a division of SpaceX, is expected to continue expanding its generator fleet. In SpaceX’s IPO filing, the company disclosed plans to purchase an additional $2.8 billion worth of gas turbines over the next three years to power its AI data centers, with at least $2 billion allocated specifically for “mobile gas turbines.”