“For instance, if all the 35 turbines operated by xAI were using” add-on air pollution control technology “to achieve a NOx emission rate of 2 ppm”—as xAI’s consultant agreed it would—”they would emit about 177 tons of NOx per year, as opposed to the 1,200 to 2,100 tons per year they currently emit,” the letter said.

Allegedly, all of xAI’s active turbines “continue to operate without utilizing best available control technology” (BACT) and “there is no dispute” that since xAI has yet to obtain permitting, it’s not meeting BACT requirements today, the letter said.

“xAI’s failure to comply with the BACT requirement is not only a Clean Air Act violation on paper, but also a significant and ongoing violation that is resulting in substantial amounts of harmful excess emissions,” the letter said.

Additionally, xAI’s turbines are considered a major source of a hazardous air pollutant, formaldehyde, the letter said, with “the potential to emit more than 16 tons” since xAI operations began. “xAI was required to conduct initial emissions testing for formaldehyde within 180 days of becoming a major source,” the letter alleged, but it appears that a year after moving into Memphis, still “xAI has not conducted this testing.”

Terms of xAI’s permitting exemption remain vague

The NAACP and SELC suggested that the exemption that xAI is seemingly operating under could be a “nonroad engine exemption.” However, they alleged that xAI’s turbines don’t qualify for that yearlong exemption, and even if they did, any turbines still onsite after a year would surely not be covered and should have permitting by now.

“While some local leaders, including the Memphis Mayor and Shelby County Health Department, have claimed there is a ‘364-exemption’ for xAI’s gas turbines, they have never been able to point to a specific exemption that would apply to turbines as large as the ones at the xAI site,” SELC’s press release alleged.