In Plymouth, plenty of residents will tell you cancer is not some abstract statistic. It is neighbors, relatives and entire streets. So when a Harvard-led monitoring project starts dropping air filters into living rooms near the shuttered Pilgrim Nuclear Power Station, people are paying attention. The new pilot will place air monitors in homes and test blood for biomarkers that could show evidence of exposure, a hands-on follow-up to a statewide analysis that found higher cancer incidence near some plants. The rollout has once again put a spotlight on the thousands of spent-fuel assemblies stored at Pilgrim while Holtec continues decommissioning work at the site.
What the Harvard paper found
The Harvard team published a statewide analysis in December 2025 that drew on Massachusetts Cancer Registry data from 2000 to 2018 and estimated that roughly 20,600 cancer cases in the state could be attributable to living near a nuclear power plant, with risk dropping as distance from a plant increased, according to a study in Environmental Health. The paper adjusted for air pollution and socioeconomic factors and reported that the association was strongest among older adults. The authors said their findings highlighted the need for exposure-level research to test whether simple proximity is really standing in for specific dose pathways.
Neighbors report clusters
On the South Shore and across Cape Cod, residents say they do not need a regression model to notice trouble. They describe cancers that seem to run along family trees and down particular streets near the plant. "So many people have had health issues, all kinds of cancers," one resident said, while another pointed to multiple cases on a single block, as Boston 25 News reported. Local activists have for years zeroed in on the high inventory of spent fuel being kept on site as a lingering risk.
What Koutrakis will measure
Petros Koutrakis, the Harvard professor who co-authored the December analysis, is now leading the new pilot that moves from maps to living rooms. The study will install air filters inside homes and collect blood samples to look for biomarkers of exposure and early biological effect. "What we will do, we measure particles inside these homes and also we will measure blood, biomarkers of exposure and effect," Koutrakis told reporters. He expects to enroll about 30 to 50 people who live near Pilgrim and compare them with residents farther away, Boston 25 News reported. The pilot is deliberately small and is built to trace potential exposure pathways rather than to settle the broader and often heated arguments over cancer rates.
Spent fuel and decommissioning
Pilgrim ended commercial operations in May 2019, and Holtec now holds the site license and is managing decommissioning and interim fuel storage. Entergy and state notices document the May 31, 2019 shutdown, and Holtec's project FAQ states that 61 dry casks will be used to store Pilgrim's used fuel. Local watchdogs and Pilgrim Watch point out that the configuration corresponds to more than 4,000 fuel assemblies kept on the property, a number that has only sharpened community anxiety. The Entergy and Mass.gov release, Holtec's FAQs and Pilgrim Watch materials lay out the official timeline and inventory details.
Controversy and criticism
The Harvard proximity findings and the new monitoring plan have drawn pushback from some industry and policy commentators who argue that a zip-code-based design cannot by itself prove causation. The Breakthrough Institute published a detailed critique contending that the Massachusetts analysis confuses simple distance with actual dose. The Harvard group has followed with a national mortality analysis in Nature Communications, which has only intensified debate over how to read spatial patterns in cancer data. Researchers on every side still land on one shared point: targeted exposure measurements are the logical next step.
What's next
The monitoring pilot is scheduled to begin this spring under a project coordinated by Greater Boston Physicians for Social Responsibility and overseen by Koutrakis. The effort received congressional funding to place outdoor ambient monitors and to coordinate community testing. Organizers say they will share their methods and results with residents once sampling and lab work are complete, while stressing that the small study is meant to track exposure pathways, not to deliver a final verdict on cancer causation. For now, the pilot offers neighbors a direct, hyper-local set of measurements to put alongside the sweeping statewide statistics.
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