Get an x-ray, and you get a small dose of radiation to visualize your bones and body structures to help you medically. Buy a smoke detector, you’re inviting a tiny source of radiation, americium-241, into your home to keep you safe. But we don’t just take on that radiation heedlessly. Until perhaps now.
The U.S. regulates the amount of radiation people are exposed to using something called the linear no-threshold model, which says that every additional dose of ionizing radiation, however small, adds a small risk to health. It’s a simple equation that describes the relationship between dose and risk. For decades it has anchored radiation dose limits for both the public and radiation workers. But by February 23, the Nuclear Regulatory Commission (NRC) is expected to overhaul its regulations, potentially retiring this risk model, per a May executive order by President Donald Trump.
Why loosen this protection? Supposedly to spur nuclear energy production. The administration says that this risk model is too cautious, leading to costly conservatism in reactor design, staffing redundancies and stringency in licensing. The executive order promises that lifting it will accelerate nuclear reactor licensing while lowering the costs of providing nuclear energy to the grid.
On supporting science journalism
If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
As a nuclear energy advocate and former Department of Energy official, I want to see more nuclear energy on the grid soon. But loosening the protections of the linear no-threshold (LNT) model is not supported by current research. Some experts warn that relaxing it could especially place women and children at higher risk of damage from radiation.
The LNT model is based on the idea that exposure to any amount of radiation proportionally increases health risks, including the risk of cancer. From data on high radiation exposures, scientists extrapolate, or predict, what might happen if people are exposed to lower levels of radiation. At low doses, however, it becomes difficult to distinguish the health effects of radiation from the other environmental and lifestyle factors that can affect health. That uncertainty is why regulators rely on a cautious approach like the LNT model, and also why some people question its use.
People are willing to accept the radiation risks inherent in medicine, industry and energy because they trust that standards have been set by credible experts relying on evidence who err on the side of caution and protecting human health. Weakening regulations without new evidence would do the opposite. The last time the question of raising the public dose limit came up, the NRC said no—there wasn’t enough evidence. We must urge the NRC’s current commissioners to demand evidence and heed science over political agenda.
Several international radiation protection organizations agree that the model is conservative. International Atomic Energy Agency standards, recommendations from the International Commission on Radiological Protection, official commentary from the National Council on Radiation Protection and Measurements, a review by France’s Institute for Radiological Protection and Nuclear Safety, and many recent papers acknowledge the evidence is uncertain at low doses.
More data are needed—this is what those organizations and the U.S. National Academies of Science, Engineering, and Medicine say. Other models for low-dose exposure have been proposed, but only additional research can test them. Until then, LNT, though conservative, remains the most defensible basis for protection.
To fill the gaps in understanding radiation risk across a range of doses, we need well-designed biological and epidemiological studies of large numbers of people. Heightened concern for vulnerable populations demands particular attention on low-dose effects across ages, sexes and exposure both at home and on the job. The U.S. must also prioritize coordination with other countries already engaged in this work.
This will require both funding and patience. In 2022 the National Academies estimated the appropriate research infrastructure and effort could cost $100 million per year for 15 years.
The language of the May executive order, coupled with an earlier order requiring that any regulatory changes align with President Trump’s policies, effectively demands that NRC’s decision-making be political rather than scientific. In their Senate confirmations, the newest commissioners, Chairman Ho Nieh and Commissioner Douglas Weaver, nevertheless promised science-led, risk-informed decision-making. Between 2015 and 2021, when the NRC methodically re-assessed and reconfirmed the LNT model, the process was public, evidence-based and rooted in international consensus. This time around, public comment has been sparse and rushed, with no suggestion of international coordination or consensus-building.
The commissioners need better data before they act. Anything less will break Nieh’s and Weaver’s promises and undermine public support for new nuclear reactors.
Where should the U.S. go from here?
We should reject changes to the current risk model until we have new data. We should fund the many researchers who are willing to do this work, and we should take into account what international research says. Moreover, the notion the public will meekly accept weaker radiation standards without explanation seems foolhardy.
Only with new data can we reassess radiation limits without political interference and have the public forum necessary to ensure transparency. Scientists, medical experts, policy makers and administrators, along with citizens who care about public health and nuclear energy, can bolster public confidence in nuclear energy by weighing in on this decision with the latest, most rigorous information possible. Scientific regulatory decision-making ought to be thoughtful, thorough and evidence-based.
There is simply no other ethical option.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.
