How Manhattan Project Waste Still Affects Health Today
A groundbreaking epidemiological study reveals the long-term health impacts of low-level radioactive waste
Seventy years after the Manhattan Project ushered in the atomic age, its radioactive legacy continues to impact American communities in startling ways. A groundbreaking epidemiological study published in JAMA Network Open has revealed that children who grew up near a contaminated creek in Missouri faced dramatically increased cancer risks throughout their lives—simply because they played near waters poisoned by nuclear waste 1 .
This research provides some of the most compelling evidence to date about the long-term health effects of low-dose radiation exposure from environmental contamination.
This research provides some of the most compelling evidence to date about the long-term health effects of low-dose radiation exposure from environmental contamination, offering crucial insights for ongoing debates about nuclear energy, weapons production, and environmental justice. The findings come at a pivotal moment as Congress expands compensation for those affected by radiation exposure and scientists intensify efforts to understand how even low levels of radiation can impact human health.
The Manhattan Project, the top-secret World War II program that developed the atomic bomb, left behind a largely overlooked public health crisis that would unfold over decades. While the devastating immediate effects of nuclear weapons were demonstrated at Hiroshima and Nagasaki, the quieter tragedy of radioactive waste management would emerge more slowly across the United States 6 .
In St. Louis, Missouri, the Mallinckrodt Chemical Works became an unexpected hub for uranium processing beginning in 1942. Company executives agreed to purify uranium ore for the war effort, eventually producing approximately 50,000 tons of purified uranium between 1942 and 1957 7 .
The radioactive waste from these operations was haphazardly stored in open steel drums next to Coldwater Creek, a tributary of the Missouri River that would become a central playground for generations of children 1 .
Government officials and corporate leaders were aware of potential dangers—a 1947 Atomic Energy Commission panel noted that uranium byproducts could pose "the gravest of problems" if discarded thoughtlessly—yet continued to neglect proper storage protocols 7 .
The situation worsened as the surrounding areas developed into suburban communities between the 1950s and 1970s, with population growing from approximately 4,000 to 85,000 residents.
Radiation exposure is measured in millisieverts (mSv), with health risks typically assessed based on dose magnitude and duration. Low-dose radiation generally refers to exposures below 100 mSv—far less than the acute exposures experienced by atomic bomb survivors but significantly above natural background levels 3 .
Epidemiologists face significant challenges in studying low-dose radiation effects. Health impacts may take decades to manifest as cancer, making cause-effect relationships difficult to establish. Additionally, researchers must account for numerous confounding factors and accurately reconstruct historical exposures that were never properly measured 3 .
| Exposure Source | Exposed Population | Approximate Annual Effective Dose | Primary Radioisotopes |
|---|---|---|---|
| Natural Background | Entire U.S. population | 2.49 mSv | Potassium-40, Uranium decay products |
| Diagnostic CT Scans | Patients (74 million) | 1.4-1.5 mSv | X-rays |
| Nuclear Power (routine operations) | Communities near plants | <0.01 mSv | Carbon-14, Cobalt-60, Tritium |
| Occupational Exposure | Radiation workers | 0.6-3.1 mSv | Various, depending on industry |
| Coldwater Creek (historical) | Local residents | Variable (unmeasured) | Thorium-230, Radium-226, Uranium-235 |
The groundbreaking Harvard study on Coldwater Creek contamination emerged from an unexpected source: a collection of baby teeth assembled between 1958 and 1970 for the St. Louis Baby Tooth Survey. This original project, which collected over 100,000 teeth, aimed to study radioactive strontium-90 absorption from atmospheric nuclear testing 1 .
Decades later, environmental epidemiologist Marc Weisskopf from Harvard T.H. Chan School of Public Health gained access to these records and initially planned to study cognitive decline. However, when study participants repeatedly mentioned Coldwater Creek and cancer cases in their communities, Weisskopf and postdoctoral researcher Michael Leung pivoted to investigating the link between childhood proximity to the creek and cancer risk 1 4 .
The study employed several innovative approaches to overcome historical data limitations:
The study findings, published in July 2025, revealed alarming correlations between childhood proximity to Coldwater Creek and subsequent cancer risk:
| Distance from Creek | Overall Cancer Risk | Increase Compared to >20 km | Radiosensitive Cancer Risk |
|---|---|---|---|
| <1 kilometer | 44% | +44% | +85% |
| 1-5 kilometers | 33% | +37% | +52% |
| 5-10 kilometers | 29% | +21% | +31% |
| 10-20 kilometers | 26% | +8% | +15% |
| >20 kilometers (reference) | 24% | - | - |
These findings demonstrate a clear dose-response relationship—a key criterion for establishing causation in epidemiology. The steadily increasing cancer risk with closer proximity to the contamination source strongly suggests that radioactive waste in Coldwater Creek caused the excess cancers 1 .
Studying the health impacts of radiation requires specialized methods and materials. Here are key components of the radiation epidemiologist's toolkit:
| Research Tool | Function | Application in Coldwater Creek Study |
|---|---|---|
| Geographic Information Systems (GIS) | Mapping and analyzing spatial data | Mapping childhood addresses relative to contamination source |
| Biomarkers of Exposure | Measuring internal dose of radiation | Analysis of strontium-90 in baby teeth (planned for future research) |
| Dose Reconstruction Models | Estimating historical radiation exposures | Modeling potential exposure levels based on distance from creek and known contamination patterns |
| Health Surveys | Collecting self-reported health outcomes | Identifying cancer cases among study participants |
| Statistical Analysis Software | Analyzing complex dose-response relationships | Calculating excess relative risks and confidence intervals |
The Coldwater Creek study emerged alongside political efforts to address historical radiation exposure. Shortly before the study's publication, Congress passed an expansion of the Radiation Exposure Compensation Act (RECA) through the "One Big Beautiful Bill." This legislation provides payments of $25,000-$50,000 to families affected by radiation-linked cancers in the St. Louis area and elsewhere 1 .
The findings also validate the long-standing concerns of community activists who noticed clusters of rare cancers among those who grew up near the creek and began collecting data themselves 7 .
The Coldwater Creek research contributes to a much larger scientific effort: the U.S. Million Person Study of Low-Dose-Rate Health Effects (MPS). This ambitious project, ongoing for 20 years, follows 30 subcohorts of radiation workers and veterans to better understand health effects from chronic radiation exposure 5 .
The MPS is particularly important because it focuses on the protracted, low-dose exposures that characterize most modern radiation scenarios, unlike the acute exposures experienced by atomic bomb survivors.
Weisskopf and his team hope to continue their research by measuring strontium-90 levels in the preserved baby teeth, which could provide more direct evidence of individual exposure levels. However, they note funding challenges for radiation research 1 4 .
As countries consider expanding nuclear power programs and modernizing nuclear weapons arsenals, understanding the health effects of associated radioactive waste becomes increasingly urgent 4 . The Coldwater Creek study serves as both a cautionary tale and a methodological innovation that could inform future research on environmental radiation exposure.
The story of Coldwater Creek illustrates how decisions made in wartime can reverberate across generations, impacting public health decades later.
It also demonstrates the power of persistent scientific inquiry combined with community activism to uncover hidden truths and secure recognition and compensation for those harmed.
As Weisskopf noted, these findings have "broader implications as countries think about increasing nuclear power and developing more nuclear weapons" . The waste from these activities "could have huge impacts on people's health, even at these lower levels of exposure" .
The Manhattan Project's legacy thus extends far beyond the initial atomic blasts that ended World War II. It continues to shape our understanding of radiation hazards, influence compensation policies, and remind us of our responsibility to manage radioactive materials with utmost care for both current and future generations.