David Thompson lives across the road from one of two data center campuses rising on San Antonio’s far West Side, each with its own gas-fired power plant. “Is it going to be safe for my family, my daughter who was just born last year,” he asked News 4 San Antonio. On Sept. 21, two national environmental groups asked a federal judge to answer a version of that question, and to shut both campuses down until it is answered.
The complaint, filed in the U.S. District Court for the Western District of Texas by Public Citizen and the Sierra Club and announced alongside the Environmental Integrity Project, names Denver-based Vantage Data Centers and Houston-based VoltaGrid, which built the on-site power plants. It alleges the companies split what are really two large industrial pollution sources into smaller pieces so each could qualify for fast-track state air authorizations instead of the full federal review.
Bexar County is classified by the U.S. Environmental Protection Agency as a “serious” violator of the federal ozone standard, the health limit for smog. In an area like that, a new major source of smog-forming pollution must go through a federal review that requires the best available pollution controls and public notice, with a chance to comment and request a hearing. The authorizations the companies obtained from the Texas Commission on Environmental Quality, the state’s environmental regulator, require none of that public process, the complaint says.
According to the complaint, the two campuses together carry about 405 megawatts of gas-fired generating capacity, “enough electricity to power a city the size of Richmond, Virginia,” plus diesel backup generators able to produce about 455 megawatts more. At the Omicron Drive campus, VoltaGrid registered 80 natural gas engines producing 264.8 megawatts in September 2024. At the Rogers Road campus, Vantage registered 33 diesel backup generators in February 2024, then added 32 more in June 2025 while telling the state the expansion would not increase potential nitrogen oxide emissions. The groups count 151 diesel generators across both sites, the San Antonio Current reported.
The suit makes four core claims. First, that each campus’s power plant and generators form a single major source and should have been permitted as one. Second, that VoltaGrid left formaldehyde out of its smog-forming emissions math, and that counting it alone pushes each plant over the major-source line “based on Defendant VoltaGrid’s own certified representations” to the state. Third, that the plants’ nitrogen oxide figures assume pollution controls the state authorizations never require. Fourth, that Vantage began running the Rogers Road campus on its diesel backup generators as a primary power source before the gas plant was finished, which the complaint says state rules forbid outside emergencies.
The groups ask the court to stop construction and operation at both campuses until the companies obtain major-source permits, and to impose civil penalties. “We are asking a court for preliminary relief,” Mary Greene, director of enforcement at the Environmental Integrity Project, told News 4.
Vantage and VoltaGrid did not respond to requests for comment from News 4 or the Current. At an earlier public hearing, Vantage officials said the diesel generators would run only in emergencies, the Current reported. The environmental agency accepted each registration, and the companies’ position before the state has been that each piece is a minor source. The complaint says neither the EPA nor Texas took enforcement action after the groups gave the required 60-day notice on July 22.
The campuses also answer one concern state leaders have raised about data centers, their strain on the grid. They generate their own electricity rather than waiting in line with other large new customers seeking a grid connection. The fight here is not over whether these data centers bring their own power. They do. It is over whether a 405-megawatt power supply can be permitted the way a small generator would be.
The suit landed the same day Gov. Greg Abbott ordered the environmental agency to stop issuing permits tied to data centers until state audits are complete, an order that, as The Texas Dispatch reported, reaches self-powered projects the grid operator’s earlier pause did not. That freeze governs new approvals. These two campuses already hold theirs, so the lawsuit is what now tests whether those approvals fit the size of what was built.
Greene said the groups will seek a preliminary order halting both sites, and the agency’s compliance report to the governor is due Oct. 19.