MTS

Wiki/Primary documents

xAI Colossus Memphis — Permits and Litigation, Annotated

Primary-document brief on the air permit, the unpermitted-operation period, the NAACP/SELC/Earthjustice administrative appeal, the federal Clean Air Act complaint, the MLGW interconnection, the Southaven (Mississippi) expansion, and the EPA rulemaking that has made the central legal question federal.

Why this case matters

xAI's Colossus 1 in southwest Memphis, and its Colossus 2 power plant in Southaven, Mississippi, are the most contentious AI-siting fight in the US — the first real test of whether Clean Air Act environmental-justice frameworks can constrain the speed at which frontier-AI companies build out gigawatts of compute. Four reasons it's load-bearing:

  1. The buildout was off-grid for its first year. xAI installed up to 35 methane combustion turbines at the former Electrolux plant on Paul R. Lowry Road without a Shelby County air permit — an estimated 1,000–2,100 tons/yr NOx, likely the single largest industrial NOx source in a Memphis MSA already in violation of federal ozone standards.
  2. The host community is Boxtown, a 99% Black neighborhood founded by emancipated freedmen in 1863, inside a southwest-Memphis industrial corridor whose modeled cumulative cancer risk is four times the US national average.
  3. The legal theory the local regulator embraced — that large gas turbines are "nonroad engines" exempt from Clean Air Act preconstruction permitting — was rejected in writing by EPA in a January 15, 2026 final rule. Shelby County's Air Pollution Control Board nevertheless upheld the permit on December 15, 2025 on a 6-1 mootness vote.
  4. The Mississippi side is the first federal Clean Air Act citizen suit ever filed against an AI company. NAACP v. X.AI Corp. and MZX Tech LLC, No. 3:26-cv-00074-MPM-JMV (N.D. Miss., filed April 14, 2026), seeks injunctive relief that would shut down Colossus 2's gas plant absent permitting and BACT.

If the NAACP wins injunctive relief it will be the first time a federal court has restrained an AI training cluster's power supply on Clean Air Act grounds. If xAI wins, "build now, permit later" becomes the operational template for the next 50+ GW of frontier-AI capex.

Timeline

Date Event
Mar 2024 xAI selects the vacant Electrolux plant at 3231 Paul R. Lowry Road for Colossus 1.
Jun 12, 2024 First satellite imagery confirms combustion turbines installed — no Shelby County air permit on file.
Jul 2024 Colossus 1 operational ("constructed in 122 days").
Aug 26, 2024 SELC, Memphis Community Against Pollution, Young, Gifted & Green and the Sierra Club Chickasaw Group send the first formal letter to SCHD Director Dr. Michelle Taylor demanding enforcement.
Nov 7, 2024 TVA Board approves a 150 MW increment for the site, contracted through MLGW.
Dec 4, 2024 xAI announces (via the Greater Memphis Chamber) that GPU count will rise from 100,000 to a minimum of 1 million — implying 1,000–1,500 MW.
Apr 9, 2025 SELC et al. send a second escalation letter. Site is operating at peak: 35 turbines, ~420 MW, 1,000–2,100 tons/yr NOx PTE.
May 8, 2025 SELC discloses xAI's air-modeling protocol to EPA for 40–90 turbines at the Tulane Road / Whitehaven site.
Jun 5, 2025 SELC files a Petition to EPA to redesignate Memphis MSA as in nonattainment for ozone — four of five regional monitors exceed NAAQS.
Jun 17, 2025 NAACP, through SELC, serves federal Notice of Intent to Sue under CAA § 304 on Musk, xAI, CTC Property LLC and CTC Holding LLC.
Jul 2, 2025 SCHD issues Air Permit No. 01156-01PC for 15 Solar SMT-130 turbines, and publishes the companion "Nonroad Engine Decision."
Jul 16, 2025 NAACP and YGG file the administrative appeal with the Memphis and Shelby County Air Pollution Control Board.
Jul 25, 2025 Brent Mayo (xAI) emails Mississippi DEQ re "plans to build energy resources at our property in DeSoto County."
Aug 1, 2025 First three unpermitted turbines installed at Colossus 2, 2875 Stanton Road South, Southaven.
Aug 18, 2025 xAI groundbreaks $80M wastewater-recycling plant in Memphis.
Dec 11, 2025 Mississippi DEQ correspondence confirms 18 turbines operating at Southaven; total reaches 27 unpermitted units by Dec. 18.
Dec 15, 2025 Shelby County Air Pollution Control Board votes 6-1 to dismiss the NAACP/YGG appeal on mootness.
Jan 15, 2026 EPA finalizes NSPS Subpart KKKK / KKKKa, closing the "nonroad engine" loophole.
Feb 13, 2026 NAACP MS serves a second Notice of Intent to Sue, targeting Southaven.
Feb 17, 2026 MDEQ public hearing on the 41-turbine Southaven permit; per Mississippi Today, "no speakers voiced support."
Mar 10, 2026 Mississippi Permit Board votes unanimously to approve the 41 permanent turbine permit for MZX Tech LLC.
Apr 14, 2026 NAACP v. X.AI Corp. and MZX Tech LLC, No. 3:26-cv-00074-MPM-JMV (N.D. Miss.), filed.

The air permit: what it authorizes (verbatim)

The operative document is Air Permit No. 01156-01PC, issued by Shelby County Health Department to CTC Property LLC — an xAI affiliate registered to the same Lakeway, Texas mailing address xAI uses in corporate filings — on July 2, 2025. The permit identifies CTC's "Type of permit" as "new construction" rather than a modification of an existing source (Construction Permit Application Evaluation and Review at 4). It covers 15 Solar SMT-130 turbines with potential NOx emissions at 87.14 tons per year (id. at 7).

It is, by the regulator's own framing, a minor-source greenfield permit. It does not require: PSD air-dispersion modeling prior to issuance; a top-down BACT determination; short-term (1-hour or 3-hour) NOx emission limits; continuous emissions monitoring (CEMS) for NOx; or emissions offsets to neutralize the project's contribution to Memphis' existing ozone NAAQS violation. It caps a 12-month rolling NOx emission rate, recorded monthly. xAI's statement on issuance: "Our onsite power generation will be equipped with state-of-the-art emissions control technology, making this facility the lowest emitting of its kind in the country."

For comparison, SCHD's draft permit for TVA Allen — issued in roughly the same window for comparable combustion turbines — does require "explicit control technology requirements," 3-hour rolling-average BACT limits, and CEMS for NOx. The NAACP/YGG appeal documents this side-by-side at Figures 2 and 3.

The companion "Nonroad Engine Decision." Issued the same day (dated June 2, 2025 apparently in error), in a letter from SCHD Technical Manager Wasim Khokhar to SELC Senior Attorney Patrick Anderson, the Health Department announced — for the first time in writing — that all "temporary" combustion turbines, regardless of size, qualify as "nonroad engines" exempt from local permitting. The Nonroad Engine Decision asserts that "no exemption is needed because stationary permitting requirements do not apply to nonroad engines or to temporary activities that do not constitute 'beginning actual construction'" (Nonroad Engine Decision at 3).

The appeal frames the practical consequence: "Under the Department's Nonroad Engine Decision, nothing is stopping xAI from installing additional unpermitted turbines at any time to meet its widely-publicized demand for additional power. … CTC can do so without any public notification or public participation (or indeed, without even any notification to the Department itself)." (Appeal at 16-17.)

The unpermitted period it ratified — quantified from satellite imagery in Appendix A — peaked at:

Date XQ5200 SMT-130 SMT-60 LM2500+G4 GE Vernova 2500 Total MW NOx PTE (tons/yr, min–max)
6/12/24 14 2 0 0 0 105.8 —
11/24/24 14 4 6 1 2 413.0 935–2,053
2/26/25 14 7 8 1 4 420+ 1,073–2,353
7/1/25 (permit issuance) 4 11 6 1 4 386.5 900–~2,000

Even after the permit issued, the appeal observes that "at least some unpermitted temporary combustion turbines remain at the Paul R. Lowry facility" and SCHD "has taken no action to require xAI to remove the unpermitted turbines."

The NAACP / Young, Gifted & Green appeal: what it argues (verbatim)

Filed July 16, 2025 by Patrick J. Anderson and Amanda Garcia of SELC, on behalf of the NAACP and Young, Gifted & Green (YGG, a Memphis-based environmental-justice nonprofit led by LaTricea Adams). 19 pages of argument plus 24 attachments and two appendices.

The factual core the appeal puts on the record:

"Beginning in early June 2024, CTC began installing and, thereafter, operating numerous gas turbines at its facility in Southwest Memphis without obtaining any air permit or other written approval from the Health Department. At peak operations, CTC had 35 turbines with a total generating capacity in excess of 420 MW — larger than some TVA power plants — with the potential to emit between 1,000 and 2,100 tons of smog-forming nitrogen oxides ('NOx') and substantial quantities of other pollutants, ranking the facility as the largest or amongst the largest emitter of smog-forming air pollution in Memphis — an area that has failed to meet EPA's air quality standard for ozone for years, a problem which is worsening."

Ground 1: the "nonroad engine" theory is contrary to law

The appeal traces SCHD's argument to a quotation of 40 C.F.R. § 1068.30 in which the Health Department conspicuously omits subsection (2)(ii): "The Department itself cited to this same definition at 40 C.F.R. § 1068.30 to support its decision that turbines can be nonroad engines, but, tellingly, omitted the key provisions that relate to NSPS."

The relevant statute, 42 U.S.C. § 7550(10), defines "nonroad engine" as one "not subject to standards promulgated under section 7411 of this title [NSPS]." Subpart KKKK applies to any turbine above 10 MMBtu/hr heat input; the smallest turbines on site — the Caterpillar XQ5200 5.2 MW units — have a 60 MMBtu/hr heat input. The Solar Taurus 60s have 61.4 MMBtu/hr. All units exceed the threshold by 6x or more.

The appeal notes Subpart KKKK's definition of "stationary combustion turbine" explicitly contemplates portability: "Stationary means that the combustion turbine is not self propelled or intended to be propelled while performing its function. It may, however, be mounted on a vehicle for portability." (40 C.F.R. § 60.4420.) And it cites EPA's December 2024 proposed rule — which SCHD pointed to as supporting its position but which says the opposite: "Both subpart KKKK and proposed subpart KKKKa apply to 'portable' turbines and so these [temporary] units would generally be covered by these subparts of the NSPS regulations if they meet other applicability criteria." (89 Fed. Reg. 101306, 101345 (Dec. 13, 2024).)

Ground 2: the permit ignored an existing major source

The appeal's second ground argues CTC was already an existing major stationary source on the day SCHD issued the permit — meaning the permit should have gone through major-modification New Source Review:

"When the Health Department issued the CTC Permit on July 2, 2025, the company was already operating at least 22 unpermitted gas turbines, including at least 11 that are not encompassed by the CTC Permit. … These turbines rendered CTC an existing, major stationary source of air pollution when the Department issued the permit."

The eleven unpermitted turbines on site at permit issuance — independent of the 15 permitted SMT-130s — alone had potential to emit "at least 560 tons of NOx per year," more than twice the 250-tpy major-source threshold under 40 C.F.R. § 51.166(b)(1)(i)(B). The PSD failure chains to BACT and ozone-NAAQS consequences — proper major-modification permitting would have required "emission limits reflecting use of the Best Available Control Technology, as well as a robust assessment of ambient air quality impacts," "especially critical given that the past four years of ambient monitoring data show the Memphis area is already violating the ozone NAAQS."

Relief requested. (1) Conclusion of Law that NSPS-subject turbines cannot be nonroad engines even if "temporary or portable"; (2) vacatur of the Nonroad Engine Decision; (3) vacatur or revocation of Permit No. 01156-01PC; (4) in the alternative, remand.

What the Board did. On December 15, 2025, after a seven-hour hearing at the University of Memphis, the Memphis and Shelby County Air Pollution Control Board voted 6-1 to dismiss the appeal on mootness, accepting xAI's representation that the unpermitted turbines had been removed. The Board declined to reach the underlying legal question.

Principals on the record:

Derrick Johnson, NAACP President and CEO: "Our health shouldn't be threatened at the hands of billionaires who circumvent the law."

Amanda Garcia, SELC Senior Attorney: "The Shelby County Health Department's decision to grant this permit not only violates federal law, it goes against the department's own regulations."

LaTricea Adams, CEO/President, Young, Gifted & Green: "Young, Gifted & Green is standing on environmental justice business and is challenging Shelby County's reckless approval of xAI's air permit."

MLGW: capacity provided, capacity not yet provided

MLGW disclosures and Memphis City Council briefings establish the utility footprint as of mid-2025:

  • 50 MW from an existing MLGW substation near the Electrolux property, completed by August 1, 2024 at approximately $760,000.
  • 150 MW contracted via TVA Board approval November 7, 2024, served through a new xAI-built substation that MLGW will assume ownership of. xAI was projected to spend ~$24M on the substation, recouped via a monthly "margin allowance."
  • Drinking water from the Memphis sand aquifer pending construction of a recycled-water facility — Protect Our Aquifer documented 1.3 million gallons/day, projected to scale toward 5 million gallons/day.
  • Wastewater / gray-water recycling: xAI announced an $80M ceramic-membrane bioreactor plant in August 2025; Musk subsequently said the project was on hold until Colossus 2 was complete. Mayor Paul Young and MLGW President Doug McGowen issued public letters pushing xAI to finish it.

What MLGW has not provided, on the record: the full 1,000–1,500 MW the December 2024 Greater Memphis Chamber announcement implied. Southern Alliance for Clean Energy summarized: "We are far from convinced that xAI didn't know when they first came to Memphis that they would expand the plans 10x." The added load is "1/3 of the current peak demand of the city of Memphis" — "roughly a full nuclear or fossil gas power plant's worth."

MLGW CEO Doug McGowen to City Council, January 2025: "It is a physics problem, not a political problem, on how much energy can be provided here."

Council members across multiple meetings registered that they had learned of the project from press coverage rather than from MLGW or the administration — a pattern repeated when xAI doubled GPU counts in December 2024 and again when the Tulane Road and Southaven sites surfaced in 2025.

Mississippi expansion as a deliberate sidestep

The Southaven facility at 2875 Stanton Road South is owned by xAI's wholly owned subsidiary MZX Tech LLC, which acquired the property in July 2025 — the same month the Memphis appeal was filed and one month after xAI received Permit 01156-01PC. The federal complaint (NAACP v. X.AI Corp. and MZX Tech LLC, 3:26-cv-00074-MPM-JMV) documents the playback at ¶ 4: "Between August and December 2025, Defendants xAI and its wholly owned subsidiary MZX Tech LLC ('MZX Tech') installed and began operating twenty-seven polluting gas turbines (the 'Colossus Gas Plant') in Southaven, Mississippi, which is in DeSoto County, without an air permit or regard for the health and safety of people living nearby."

From paragraph 132: "In July 2025, Brent Mayo, holding himself out as a representative of 'XAI,' informed the Mississippi Department of Environmental Quality ('MDEQ') of 'our plans to build energy resources at our property in DeSoto County,' using combustion turbines." Trinity Consultants' emails to MDEQ (Exhibit C) log the install sequence: three SMT-130s on Aug. 18, 2025; ten TM2500s + seven SMT-130s by Sept. 6; an M35 added Sept. 10 for "a combined total output of 400.5 megawatts"; by Dec. 11, twenty-seven turbines onsite.

The complaint's introduction is unusually blunt: "'Move fast and break things' is the unofficial motto of the tech industry. As the motto promises, artificial intelligence company Defendant X.AI Corp. ('xAI') and its subsidiaries broke Clean Air Act requirements that protect public health when rushing to build gas power plants for their 'Colossus' data centers in the greater Memphis area." (¶ 1.) "xAI even boasts on its website about the speed of construction 'outpacing every estimate.' Indeed, xAI and its subsidiaries have tried to outrun the Clean Air Act by repeatedly building gas power plants for these data centers — in communities in the greater Memphis area with significant Black populations — without obtaining mandatory permits." (¶ 2.)

Three counts:

  1. First Claim: stationary source constructed/operated without a Mississippi SIP permit (11 Pt. 2 Ch. 2 Miss. Code R. 2.1).
  2. Second Claim: major source constructed/operated without a PSD permit or BACT. "The twenty-seven unpermitted turbines have the potential to emit over 1,700 tons of smog-forming NOx, likely making the Colossus Gas Plant the largest industrial source of NOx in the greater Memphis area" (¶ 8).
  3. Third Claim: major source of hazardous air pollutants (formaldehyde) without NESHAP Subpart YYYY compliance.

Civil penalties of up to $124,426 per day per violation. Prayer for relief (¶¶ a-g) seeks to "permanently enjoin Defendants from operating the Colossus Gas Plant … except in accordance with the Clean Air Act and all applicable regulatory requirements."

The Mississippi side matters for two reasons. First, the unpermitted-buildout pattern was replicated between July and December 2025 — entirely after the Memphis public fight and after the federal NOI was served. Second, the complaint flags that "xAI is planning a third data center ('Colossus 3') even closer to the Colossus Gas Plant" (¶ 11), about 0.8 miles away (¶ 219).

Three weeks before the federal suit, the Mississippi Environmental Quality Permit Board granted MZX Tech a construction permit for 41 permanent turbines (March 10, 2026, unanimous), intended to replace the 27 unpermitted units. SELC: "Mississippi regulators rubber-stamp[ed] [the] air permit for xAI power plant, ignoring overwhelming public pushback." Mississippi Today reported that at the February 17, 2026 hearing, "no speakers voiced support for the proposal."

The environmental-justice frame

Boxtown. Founded in 1863 by emancipated freedmen — the houses originally built from repurposed railroad boxcars. Memphis annexed the neighborhood December 31, 1971. Per census data cited in the air-permit record, it's 99% Black. The surrounding industrial corridor hosts "18 facilities that release deadly toxins" and at least 32 industrial facilities within a five-mile radius — a Valero refinery (195,000 bbl/day to the north), the Sterilization Services of Tennessee ethylene-oxide plant, iron and steel works, a pesticide manufacturer. A 2013 study put cumulative cancer risk from toxic air at four times the US national average, driven by benzene and formaldehyde.

Air monitoring. The June 5, 2025 SELC Petition to Redesignate the Memphis MSA as in Nonattainment for Ozone (Attachment 1 to the NAACP/YGG appeal): "Certified ambient air quality monitoring data collected over the past four years show that this area is in violation of the 8-hour primary NAAQS for ozone. … Three years ago, all five monitoring sites had design values below the federal standard, whereas four of these sites now have design values that clearly violate the NAAQS." The American Lung Association gives Shelby County an "F" on ozone; Memphis is one of the nation's "asthma capitals."

Voices on the record. State Rep. Justin Pearson (D-Memphis): "The amount of tax money is not worth our lives. … We're seeing exploitation of an already vulnerable community by really ultra-powerful, ultra-wealthy interests." Abre' Conner, NAACP: "A data center should not be a potential death sentence for a community's [health]."

EPA Region 4 and the federal rulemaking

Two federal threads matter. (1) EPA Region 4 guidance long held that "temporary" combustion turbines fall outside Title V if they operate at a site for fewer than 364 days. This underpins SCHD's "Nonroad Engine Decision" and MDEQ's initial determinations to Brent Mayo — and is the operational basis for the "rotate every 11 months" evasion the SELC briefing repeatedly flags. (2) The January 15, 2026 final NSPS Subpart KKKKa rule clarifies that combustion turbines used in "long-term, site-bound roles" are stationary "even when portable" — closing the nonroad loophole on the federal side. SELC: "EPA confirms that large methane gas turbines require permits."

The Memphis appeal had cited the December 2024 proposed version of this rule; the final rule was published one month after Shelby County upheld the Nonroad Engine Decision on mootness. The Mississippi federal complaint pleads NSPS-stationary status without needing to invoke the rule directly, because Subpart KKKK's existing "stationary" definition already covers the turbines. EPA has not, as of the record reviewed, opened a federal enforcement action against xAI, CTC Property LLC, or MZX Tech. The principal federal pressure point remains the NAACP citizen suit.

xAI's own statements

  • xAI press statement, Jul 2, 2025 (on Permit 01156-01PC): "Our onsite power generation will be equipped with state-of-the-art emissions control technology, making this facility the lowest emitting of its kind in the country."
  • Musk on X, late 2025: "The Colossus 2 supercomputer for @Grok is now operational. First Gigawatt training cluster in the world. Upgrades to 1.5GW in April."
  • Musk on X, Dec 30, 2025: discloses purchase of a third building near Colossus 2, bringing total site capacity "to nearly 2 gigawatts."
  • xAI website (Compl. ¶ 2): brags about construction speed "outpacing every estimate."
  • Brent Mayo to MDEQ, Jul 25, 2025: "our plans to build energy resources at our property in DeSoto County."
  • Greater Memphis Chamber, Dec 4, 2024: announces xAI will scale "to a minimum of one million GPUs."

xAI has not published a Colossus-specific environmental disclosure, an air-monitoring commitment, or the contractual terms of its TVA / MLGW agreement. The TVA Board approval of Nov. 7, 2024 (for 150 MW) is the only publicly disclosed power-supply contract instrument.

Open questions

  1. Will the Northern District of Mississippi grant the NAACP's preliminary injunction? Relief sought would halt the 27-turbine Colossus 2 power plant. xAI will likely lean on the March 10, 2026 MDEQ permit for 41 replacement turbines as constructive cure — a mootness theory analogous to the one Shelby County's board accepted.
  2. Will Tennessee state courts review the Air Pollution Control Board's mootness dismissal? SELC has flagged but not yet publicly filed a chancery-court certiorari petition.
  3. What happens at the Tulane Road / Whitehaven site? May 8, 2025 SELC disclosed xAI consultant air-modeling correspondence with EPA for 40–90 turbines there. The Chamber publicly denied turbines would be sited there in May 2025; the Daily Memphian reported turbine stockpiling at a vacant Southaven lot in June 2025. No public permit application yet.
  4. Will EPA's January 15, 2026 final NSPS rule survive industry challenge? If stayed, the central legal theory of the NAACP filings weakens.
  5. Does the MLGW $24M margin-allowance reimbursement constitute a state subsidy subject to disclosure or rate-payer challenge? Council records remain thin.
  6. What did the SCHD Director know, and when? Five SELC and partner letters on file (Aug. 26 / Sept. 10, 2024; March 26 / April 9 / April 30, 2025) and one NAACP letter (May 29, 2025) preceded the permit. The June 17, 2025 NOI was hand-delivered to Dr. Michelle Taylor two weeks before issuance. Mootness leaves these unexamined.
  7. Will Colossus 3 — flagged in the complaint at ¶ 219 as ~0.8 mi from the Southaven plant — follow the same install-first pattern? No public power-source disclosure exists.

Sources — direct URLs to primary documents

Primary filings (load-bearing).

Regulatory.

Press releases and analyses referenced for quotations.

Quotations herein are verbatim from the primary filings — principally the NAACP/YGG appeal and the federal complaint at 3:26-cv-00074-MPM-JMV.