The rapid expansion of mega data centers across the United States is drawing sharp criticism from environmental researchers and public health advocates who argue the industry’s pollution footprint has been underestimated. Powered by banks of diesel backup generators and fed by fossil-fueled electricity grids, these facilities can emit hazardous pollutants that regulators and communities are increasingly scrutinizing. As the AI boom accelerates construction timelines, some experts and advocates warn that data centers could be among the dirtier large-scale industries operating in American communities today, particularly where projects cluster.
Virginia’s Air Permits Expose Generator Sprawl
Virginia has become the epicenter of U.S. data center development, and the state’s environmental regulator has responded by building one of the most detailed public records of the industry’s air emissions footprint. The Virginia Department of Environmental Quality now maintains a public index of issued air permits for data centers. This registry allows the public to see which projects qualify as Title V major sources versus minor New Source Review permits, a distinction that determines how much regulatory oversight a facility receives and what kind of pollution controls it must install.
What the permit data suggests is striking. Data center campuses may house many diesel generators, and in some cases the cumulative emissions from these units can trigger more stringent permitting requirements for pollutants such as nitrogen oxides and particulate matter. Critics argue the permitting framework can still treat each campus in isolation, failing to account for the combined air quality burden when multiple data centers cluster in the same county. For residents of northern Virginia, where data center density is among the highest in the nation, this means the total pollution load from neighboring facilities could be higher than what any single permit implies, especially on days when multiple backup units are tested or run simultaneously during grid disturbances.
Diesel Health Risks Quantified in Quincy, Washington
The health consequences of diesel exhaust from data center generators are not theoretical. In Quincy, Washington, a small agricultural community that became home to several large data center campuses, regulators sought a formal accounting of diesel particulate exposure. The resulting technical document, a revised health risk assessment submitted to the Washington State Department of Ecology, attempted to quantify modeled cancer risk estimates for nearby residents based on emissions from backup engines. The report was produced in response to proceedings involving the Pollution Control Hearings Board (PCHB) following local complaints and legal challenges.
The methodology section of the Quincy report details the emissions inventory choices, atmospheric dispersion assumptions, and exposure pathways used to estimate risk, including how often generators run, how pollutants travel in local wind patterns, and how long residents are assumed to be exposed. Some critics of industry-funded analyses argue that when regulated entities or their consultants produce studies used in permitting, assumptions can be selected that reduce modeled impacts, such as limiting the number of hours engines are modeled to operate. For the families living near these facilities, the question is whether modeled risk estimates capture real-world exposure patterns, especially for children and outdoor workers who may spend more time breathing ambient air than the average adult assumed in standard risk models.
Peer-Reviewed Research Flags Broader Pollution Links
Beyond individual state-level disputes, the scientific literature is beginning to frame data center pollution as a systemic public health concern. A peer-reviewed analysis in a medical journal found that fossil-fueled power plants and diesel backup generators powering data centers emit nitrogen oxides and other hazardous pollutants that may elevate cancer risk in nearby communities. The authors emphasized that these emissions contribute not just to acute respiratory irritation but also to long-term disease burdens, particularly when multiple facilities concentrate in a single airshed. They concluded that the current evidence base is far too thin given the speed at which new data centers are being built worldwide.
This gap between construction pace and health research is more than an academic problem. The industry has scaled faster than the epidemiological tools needed to measure its effects on surrounding populations, leaving regulators to rely heavily on modeling rather than observed health outcomes. The peer-reviewed analysis underscores how limited the available empirical evidence is in communities adjacent to data center clusters, including in regions that have seen especially intense build-outs. Without stronger data, environmental agencies can end up permitting facilities based largely on projections, with limited capacity to detect subtle but widespread harm that might emerge over decades.
Public Opposition and Petrochemical Ties
Community resistance to data center construction is no longer confined to a handful of rural towns. Joe Romm, writing for a climate-focused advocacy group and republished through a University of Pennsylvania program, documented how public opposition is spreading as residents learn more about the fossil fuel infrastructure required to keep these facilities running. His analysis for Moms Clean Air Force highlighted increased scrutiny of the industry’s ties to major petrochemical companies, raising questions about whether the “clean tech” branding of AI and cloud computing obscures a dependence on some of the world’s largest fossil fuel producers. Local campaigns have begun to link data center projects with broader fights over pipelines, gas plants, and petrochemical build-outs.
This framing challenges a dominant assumption in corporate sustainability messaging: that data centers are primarily an electricity problem solvable through renewable energy procurement. While solar and wind contracts get prominent billing in annual reports, the diesel generators that provide backup power during grid outages operate under separate air permits and burn fossil fuel directly on site, often in neighborhoods that receive few of the economic benefits of the digital economy. Commentators and advocates also argue that meeting rapidly growing data center electricity demand can encourage additional fossil-fueled generation in some regions, potentially locking in longer-lived infrastructure. For communities living downwind, the distinction between a data center’s grid electricity source and its on-site combustion equipment is not academic; it can affect what they breathe on test days, during storms, and whenever the grid falters.
Regulatory Gaps and the Road Ahead
The current regulatory structure has struggled to keep pace with the speed and scale of data center expansion. Air permitting frameworks in states like Virginia and Washington were designed around traditional industrial sources such as factories and refineries, not campuses containing hundreds of megawatts of IT equipment paired with fleets of high-horsepower generators. As a result, regulators often evaluate each facility in isolation, using thresholds that may not fully capture the cumulative impact of multiple data centers clustered in a single region. In many jurisdictions, backup generators are treated as intermittent sources with limited operating hours, which can justify looser controls even though emergency events and frequent testing can add up to significant annual emissions.
Closing these gaps will likely require regulators to rethink how they categorize and assess digital infrastructure. Advocates are calling for cumulative impact analyses that consider all data centers within a given airshed, stricter limits on diesel generator testing near homes and schools, and requirements that new projects prioritize non-combustion backup systems where feasible. Some public health experts argue that permitting decisions should be conditioned on transparent health risk assessments conducted by independent researchers rather than consultants hired by project developers. As AI-driven demand pushes companies to propose ever-larger campuses, the road ahead will be defined by whether permitting agencies, legislators, and communities insist on treating data centers as major industrial polluters subject to robust oversight, or allow them to remain cloaked in the rhetoric of a clean, virtual economy while their physical exhaust stacks grow taller on the horizon.
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*This article was researched with the help of AI, with human editors creating the final content.
