Harvard Scientists Persist Despite Administration Pressure
A recent paper has been generating discussion on social media after reporting that counties located closer to operating nuclear power plants (NPPs) in the United States show significantly higher cancer mortality rates.
According to the paper, “National analysis of cancer mortality and proximity to nuclear power plants in the United States,” published on February 23, 2026 in the international journal Nature Communications, approximately 115,586 cancer deaths between 2000 and 2018 may be attributable to proximity to nuclear power plants.
This corresponds to more than 6,400 deaths per year on average.
At the same time, the article also notes strong pushback from some scientists, who argue that the study lacks credibility because it does not include actual radiation dose measurements.
One of the major difficulties in studying low-dose radiation exposure—generally defined as exposure below 100 millisieverts—is that it is extremely hard to identify clear causal relationships.
“Even the smallest amount of radiation exposure is assumed to carry a health risk proportional to the dose, and there is no safe threshold below which radiation is considered harmless. Radiation protection policies follow this assumption through the internationally adopted Linear No-Threshold (LNT) model.”
— Chugoku Shimbun, July 26, 2016
Based on this definition, the Harvard study initially appeared reasonable to me. However, the backlash from parts of the scientific community seems quite significant.
The epidemiological study was conducted by a research team at the Harvard T.H. Chan School of Public Health.
The paper’s corresponding author, Petros Koutrakis, a professor of environmental health, reportedly emphasized that:
“As nuclear energy is increasingly promoted as a clean solution to climate change, further research on nuclear power plants and their potential health impacts is essential.”
He also pointed out that completely ignoring a signal of more than 6,400 estimated deaths per year would itself pose risks from a public health perspective. It seems clear that the researchers hope their work will stimulate debate and lead to more comprehensive studies.
The Harvard School of Public Health and the “Baby Tooth Survey”
In fact, the Harvard School of Public Health is also well known for its work related to the Baby Tooth Survey.
The preserved materials from the original survey conducted by women in St. Louis—and modern research based on those materials—have been carried on there.
In 2001, roughly 100,000 untested baby teeth were discovered in storage at Washington University in St. Louis.
These samples were later transferred to researchers including Marc Weisskopf at the Harvard T.H. Chan School of Public Health.
How did the baby teeth collected in St. Louis end up at Harvard?
As fans of the film may remember, Joseph Mangano, executive director of the Radiation and Public Health Project (RPHP), explained the story in an interview with the director.
One day, while I was working in my office, I received a phone call from Daniel Cole, a biology professor at Washington University in St. Louis.
He said, “I went to look through the university warehouse and found baby teeth.”
We had believed that all 320,000 teeth collected during the original study had already been used for testing. But it turned out that 101,000 of them had never been examined.
To test the teeth, they must be ground into powder and placed into liquid. In other words, the teeth must be destroyed. That was the reason they remained unused.
He asked, “Do you want them? Washington University doesn’t.”
That’s how they were donated to RPHP. I felt like we had been given a once-in-a-lifetime opportunity.
Each tooth was stored in a small envelope along with a card containing information about the donor. We digitized all of that data and used parts of the teeth for our research.
We identified the teeth of individuals who died from cancer before the age of 50, then measured strontium-90 levels in those teeth and compared them with those of healthy individuals who were still alive at age 50.
The results showed that the cancer group had more than twice the amount of strontium-90 compared with the healthy group. We published these findings in a medical journal.
What we want to do now is expand the study using a much larger sample.
A major turning point came in 2016 when we were introduced to Professor Marc Weisskopf of Harvard’s School of Public Health.
He secured a five-year grant from the U.S. National Institutes of Health. During the first year, funding was used to digitize the records. All the data for the 101,000 teeth was fully entered into digital files by 2021.
(From interview notes with Mangano, July 12, 2022.)
New Findings from the St. Louis Baby Teeth Study
Researchers are now tracking the current health status of the individuals who originally donated their baby teeth. They are analyzing how childhood exposure to radiation and heavy metals may influence the risk of diseases later in life, including:
cancer
cognitive decline
ALS (amyotrophic lateral sclerosis)
In 2025, new findings were published.
Using participant data from the St. Louis Baby Teeth and Later-Life Health Study (SLBT), researchers found that the closer participants had lived in childhood to Coldwater Creek, a tributary of the Missouri River in northern St. Louis, the higher their lifetime cancer risk appeared to be.
Among 4,209 SLBT participants (currently averaging 63 years of age), 1,009 reported having developed cancer.
The reported cancer rates were:
30% among those who lived within 1 km of the creek
28% among those 1–5 km away
25% among those 5–20 km away
24% among those living more than 20 km away
Researchers Continuing Their Work
Professor Weisskopf and his colleagues are reportedly now also confronting obstacles from the current administration.
For the sake of public health and the protection of people’s lives, I would like to express my support for these Harvard researchers who continue their work despite political resistance.
