After thermal imaging appeared to show that xAI lied about suspected pollution at its Colossus supercomputer data center located near predominantly Black communities in Memphis, Tennessee, the NAACP has threatened a lawsuit accusing xAI of violating the Clean Air Act. In a letter sent to xAI on Tuesday, lawyers from the Southern Environmental Law Center (SELC) notified xAI of the NAACP's intent to sue in 60 days if xAI refuses to meet to discuss the groups' concerns that xAI is not using the requisite best available pollution controls. To ensure there's time for what the NAACP considers urgently needed negotiations ahead of filing the lawsuit, lawyers asked xAI to come to the table within the next 20 days. xAI did not respond to Ars' request to comment on the legal threat or accusations that it has become a major source of pollutants in Memphis. xAI accused of ignoring Black communities’ concerns According to the NAACP's letter, xAI's ambitions to build the world's largest AI data center in Memphis has potentially introduced the largest source of nitrogen oxides (NOx), reducing air quality in a city already grappling with high rates of emergency room visits and deaths from asthma. In Boxtown, a neighborhood closest to the data center, residents face "cancer risk four times the national average," due to "industrial pollution from dozens of industrial facilities, including an oil refinery, a steel mill, and a TVA gas plant." The letter stressed that all estimates of xAI's suspected pollution levels were "based on the most conservative emission factors," emphasizing that the situation may be even worse than the NAACP suggests. Because of Memphis' history of exceptionally poor air quality, any new source of pollutants requires permitting and emissions testing. The NAACP and SELC allege that, in its rush to power its supercomputer, xAI did not seek or conduct either of those prior to running methane gas turbines without proper controls.