Radiation and Public Health

Within days of the start of the Japanese nuclear emergency, the NRC made statements that no unsafe levels of radiation would impact the U.S. Other federal agencies also concluded the radiation reaching the U.S. from the damaged Japanese reactors would not be at levels of public health concern.

What does that actually mean? Radiation released from Japan had to travel a very far distance to arrive in the U.S.—while all along the way being diluted by wind, rain, and radioactive decay. Even the two closest states – Hawaii and Alaska – are still a distance away from the source of radiation.

We expected to detect trace amounts of radiation from the Japanese reactors in the U.S.—modern radiation detection equipment is very sensitive and able to detect very small amounts of radioactivity. However, just because something is detected doesn’t mean it’s hazardous.

Scientists estimate that we receive a dose of about 620 millirem each year from natural sources – like radon – and human sources – such as x-rays. There are NO known health impacts from this typical annual dose. To put this into context, even people living in places where the background radiation is much higher – such as Denver, Colo., where the rate of background radiation is above 1,000 mrem a year – don’t experience adverse health effects.

The U.S. EPA and Department of Energy concluded from their environmental monitoring of the Japanese radioactivity in the U.S. that peak concentrations of particles and gas detected in California or Washington State were 100,000 times less than the dose rate from background sources.

Radiation experts make the conservative assumption, as part of an overall radiation protection philosophy, that any amount of radiation may increase the risk for cancer and damage to DNA, and that the risk increases as the radiation exposure increases. And we do know that high doses of radiation may cause cancer. But there are no studies that clearly show cancer being caused by exposure to low doses of radiation – considered to be below about 10,000 mrem.

The bottom line? The radiation coming from the Japanese emergency can be detected by sensitive instruments, but that does not mean it’s a public health concern. The levels of radiation detected in the U.S. are well below radiation standards and only a small fraction of the average background of radiation we are exposed to in everyday life.

For additional information on radiation protection and health effects visit the NRC website at http://www.nrc.gov/about-nrc/radiation.html.

Sara Mroz
Emergency Preparedness Specialist

Author: Moderator

Public Affairs Officer for the U.S. Nuclear Regulatory Commission

9 thoughts on “Radiation and Public Health”

  1. These kind of post are always inspiring and I prefer to read quality content so I am happy to find many good points here, writing is simply great.

  2. My concern for radiation has been enhanced since the quake in Japan. Shortly after, in May I visited Tokyo for the first time and you can see the effect mentally it had on the population there. I still think it has to be a concern here in the States over time.

  3. “But your charter is essentially scientific – so when science (not assumption) repeatedly shows that small amounts of radiation are hormetic rather than harmful, NRC staff should have the courage to turn this reality into policy.”

    If the NRC’s charter is scientific, then it is obliged to use standard scientific methods. Hormesis, while having support from some members of the scientific community, remains a controversial and debated theory. At this time, there is insufficient evidence from scientific trials, particularly in humans, to warrant moving away from a LNT. The National Research Council arm of the National Academy of Sciences performed a 16 year study that rejected hormesis. It has also not received support from UNSCEAR, National Council of Radiation and Protective Measurements, Harvard School of Medicine, or any other widely respected scientific body. L’Academie des Sciences in France published a study demonstrating a positive effect in something like 1/3 – 1/2 of test results with the caveat that the effect in humans required further testing. The current studies on low-dose radiation have seen across the board results, demonstrating no effect, to benefits, to harmful effects. Perhaps with time and more study, low-dose radiation will prove to be of demonstrated benefit but until rigorously controlled studies can be completed to confirm those results, it would be irresponsible for the NRC to adopt a position that is an unproven theory. Personally, I would like to think of the NRC’s primary role as a conservative regulatory agency, and one who enforces the practice of sound and well-proven scientific principles, rather than imposing Americans to some theorie du jour.

    I don’t quite understand your aspirin analogy. I don’t recall an irrational fear that has caused harm. I am a healthcare practitioner. The consensus thinking about aspirin remains that unless one suffers from certain conditions, taking daily is not recommended. One needs to consult their physician before embarking on this regimen. It is not globally of benefit and in some circumstances can be contraindicated.

  4. The NRC has a “metrication policy” that states the NRC shall use “…the system of units employed by the licensee.” Since the Japanese officials used SI units, that is the measurement we used (even though Japan is not one of our licensees). Along with many other things associated with the Japanese nuclear emergency, though, this is something we may be reviewing.

  5. Honestly I’m not particularly concerned about health risks from radiation here in the U.S. Before March 11, I had little interest in nuclear energy and even less knowledge of the subject. However I know people that are worried about radiation risks over here. They see the contamination continuing in Japan and the evacuation zone widening. After weeks, months of hearing their government assure them everything was okay, the Japanese are now being told there were full meltdowns of the cores. They were lied to, they don’t trust their government anymore. Meanwhile in our country the decision was made weeks ago to eliminate the release of EPA radiation test results. The timing could not have looked anymore suspicious to anxious individuals. The NRC refrained from making definitive public statements about the status of Fukushima. Instead platitudes were shared of “we don’t know what is going on but don’t worry, everything is fine.” Huh? I think the NRC is oblivious to the kind of appearance they portray to the public. They operate in the shadows, on a “need to know” basis where few need to know, seemingly unaware of the potential consequences of their opaque behavior in an environment where the very future of nuclear energy is at stake. Including other pieces of the picture, such as the defunding of Yucca Mountain, and it almost seems as if the NRC is attempting to sabotage the industry.

    For me, it isn’t the technology or radiation risks inherent to nuclear energy that scares me. The fossil fuels we use come with their own bag of risks that historically have been considerably higher. What scares me is that IF we did have an accident like at Fukushima, could we expect the same cover-up? So far, the evidence seems to point to that.

  6. “Radiation experts make the conservative assumption, as part of an overall radiation protection philosophy, that any amount of radiation may increase the risk for cancer and damage to DNA, and that the risk increases as the radiation exposure increases.”

    NRC, as one of the leading authoritative experts on radiation protection, needs to take a serious look at moving away from the Linear Non-Threshold theory of radiation damage.

    The poison is in the dose. If we take 100 aspirins in a day, it will kill us; 10 will make us sick; one is probably good for us. The irrational fear and expense associated with protecting us from that one aspirin has not been beneficial to us as a technologically advanced society.

    I realize that there is a vast amount of public radiophobia out there (see previous posts), and as a government agency the NRC must sometimes maintain a politically-correct posture. But your charter is essentially scientific – so when science (not assumption) repeatedly shows that small amounts of radiation are hormetic rather than harmful, NRC staff should have the courage to turn this reality into policy.

  7. The public is more familiar with the new units of mSv after recent media coverage of radioactivity. Would you consider shifting to the newer units (perhaps with the older units in ()) to make life easier for the rest of us? I teach high school physics, and it is inconvenient that there are at least two units for everything!!!

  8. I realize there are many pollutants in our environment. But I still question whether “levels of public health concern” consider health impacts over the long term.

  9. What was background level in these places before 1940? Type of radioactive material will determine better cancer rates… it is here, but more is getting here every day predicted for at least another year to come… this will accumulate because of the ridiculously long half life of the particles… Please don’t talk about this like it is over till it is no longer releasing radioactive smoke steam and dust ash from fires… This thing, has been for three months constantly leaking highly radioactive water into the ocean. Does this ocean dumping not concern anybody enough to recognize. This may end the whale wars…

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