Counties Nearest Nuclear Plants Have Higher Cancer Death Rates, National Study Finds

Whether living near a nuclear power plant increases cancer risk has been debated for decades, with studies across multiple countries producing conflicting results. In the United States, research has been limited and fragmented - focused on single facilities or small geographic areas, with inconsistent methodologies that make cross-study comparison difficult. A new national analysis by researchers at the Harvard T.H. Chan School of Public Health represents the most comprehensive U.S. effort in more than 20 years, and it finds a consistent association between proximity to operational nuclear plants and elevated cancer mortality.

The study, published in Nature Communications on February 23, 2026, examined cancer death rates in every U.S. county from 2000 to 2018, using a continuous proximity approach that captured the cumulative influence of all nearby plants rather than treating each facility in isolation. After controlling for a range of potential confounders, the association persisted - but the researchers are explicit that the study does not establish causality.

How the Study Was Structured

Senior author Petros Koutrakis and colleagues obtained the locations and operational histories of U.S. nuclear power plants from the Energy Information Administration, including some facilities in Canada that sit close to the U.S. border. County-level cancer mortality data came from the Centers for Disease Control and Prevention. The analysis covered the full 2000-2018 period, during which approximately 93 commercial nuclear reactors were operating across 58 plants in 29 states.

The key methodological feature was continuous proximity modeling. Rather than creating a simple inside-or-outside boundary at a fixed distance, the analysis treated proximity as a continuous variable, allowing the statistical model to estimate how cancer mortality risk changes as a function of distance from the nearest plant or plants. Counties with multiple nearby plants had their exposure estimated as the combined, distance-weighted effect of all surrounding facilities.

The model controlled for educational attainment, median household income, racial composition, average temperature and relative humidity, smoking prevalence, body mass index, and proximity to the nearest hospital. These adjustments were intended to isolate the association with nuclear plant proximity from other factors known to influence cancer rates.

The Findings and Their Scale

Counties closer to nuclear power plants showed higher cancer mortality rates even after accounting for the control variables. The association was strongest in older adults. Over the 18-year study period, the researchers estimated that approximately 115,000 cancer deaths across the United States - or roughly 6,400 per year - were statistically attributable to proximity to nuclear power plants based on the magnitude of the association they found.

"Our study suggests that living near a NPP may carry a measurable cancer risk - one that lessens with distance," said Koutrakis. "We recommend that more studies be done that address the issue of NPPs and health impacts, particularly at a time when nuclear power is being promoted as a clean solution to climate change."

What the Study Cannot Determine

The researchers were direct about the study's limitations, and they matter significantly for interpreting the findings.

First, the study did not incorporate direct radiation measurements. It assumed that all nuclear power plants contribute equally to radiation exposure as a function of proximity, without accounting for differences in plant type, reactor design, cooling systems, documented emission records, or historical incident history. This is a substantial assumption that could either inflate or deflate the measured association depending on which plants actually contribute most to any real exposure.

Second, the study is observational and ecological - it uses county-level averages rather than data on individual people. This means it cannot account for which specific residents live closest to plants, how much time they spend there, or individual exposure histories. Ecological correlations of this kind are known to be susceptible to confounding by factors not captured in the model.

Third, the mechanism by which proximity might increase cancer risk - assuming the association is causal - is not addressed. Nuclear power plants in normal operation emit very low levels of radiation, generally estimated to be far below natural background levels for people living nearby. Whether any component of that emission, or some non-radiological factor correlated with plant siting, could account for the observed mortality difference is an open question that the study design cannot answer.

The findings are consistent with a similar Massachusetts-focused study the same group published previously. They arrive at a moment when nuclear energy is receiving renewed policy attention as a potential low-carbon electricity source, making the question of its health impacts - at the population level and over long time periods - more consequential than it has been in decades.