The U.S. Environmental Protection Agency, or EPA, last updated its Clean Air Act Resources for Data Centers page on Sept. 14, 2026. The page frames federal air oversight of AI data centers as cooperative federalism, meaning EPA sets the floor and states and localities issue most permits. It is a hub of existing Clean Air Act rules, modeling tools and case-by-case technical help rather than a new AI-specific national air standard. That leaves most decisions about data-center air pollution with states and localities just as outside estimates of the health costs of that pollution are climbing.
On that page, EPA says state and local air agencies issue most data-center air permits under programs approved as meeting federal minimum requirements. The same page still points operators to New Source Performance Standards and National Emission Standards for Hazardous Air Pollutants, federal emission rules for the turbines and engines data centers often use for power. It also points to standards for portable engines known as nonroad engines, New Source Review (NSR) and Prevention of Significant Deterioration permitting, and EPA modeling guidance.
The explicit statement that EPA will not set nationwide environmental requirements or recommendations for AI data centers came from Administrator Lee Zeldin, speaking at an energy summit on June 10, 2026. Zeldin said states and local communities should decide what practices are appropriate. Those were spoken remarks, not EPA rule text.
Separately, on May 11, 2026, EPA proposed clarifying "Begin Actual Construction" so that certain parts of projects for essential power, data centers and manufacturing that do not themselves emit pollution could be built before a major New Source Review permit, if the proposal is finalized. The proposal does not remove the underlying NSR permit requirement for sources that emit covered pollution, and it is still a proposal, not a final rule.
On Sept. 10, 2026, the Environmental Protection Network (EPN), which represents more than 800 former EPA employees, released a report called The Hidden Health Costs of AI Data Centers. It cites a 2026 study estimating that by 2028, data-center air pollution could cause about $11.7 billion to $20.9 billion a year in public-health costs, with roughly 600,000 cases of asthma symptoms and 1,300 premature deaths in the study's high-growth scenario. EPN says the pollution can come from generators and turbines at the data centers and from power plants farther away. Those figures are estimates from a model, not harm already observed, and they do not measure the effect of EPA's decision to leave permits to states.
EPN also lists at least 30 federal actions since January 2025 that it says raise pollution-related health risks as data centers expand, 17 of which explicitly target AI or data centers. It is not yet clear how the mix of state and local permits, the federal turbine, engine and NSR rules that still apply, and the risk of lawsuits brought by citizens will fit together, or whether health costs will rise if safeguards or fossil-fuel power differ from what the study assumed.