XKCD's radiation dose chart


[click chart to embiggen] There has been much talk of radiation exposure levels in the news, and here on Boing Boing, this past week. But it can be hard to wrap your head around what those measurements mean, and how they compare to things you may have already experienced in life. Well, it was, until XKCD created this exceptionally helpful chart showing exactly how much radiation exposure you might encounter by doing something like flying from LA to NYC, getting a chest x-ray, hanging out at Chernobyl, living near the troubled Fukushima Daiichi nuclear power plant in Japan, or sleeping next to another human being. This rules.


  1. Thank you thank you thank you. Useful. Concise. Easy to comprehend.

    So much better than pointless conjecture and fear-mongering. . .

    “The facts ma’am, just the facts.”

  2. A wonderfully useful chart.

    Sadly, I can visualize a similar chart, showing how many people will pay attention to various kinds of content:

    .. Scientifically literate, objective information

    ……………………….. “OMG Radiation!!!”

    [Next order of magnitude]

    …… Charlie Sheen

  3. So when radiation levels at Fukushima 1 were about 800 mSv/hour — the equivalent would be eating 80,000,000 bananas in an hour. That’s a lot of fucking bananas.

    1. math is hard!

      The difference between m and µ has you properly, asshattingly, hung up, doesn’t it?

      1. No way dude, the metric system is my friend. My problem is referencing wikipedia, they say 0.0001 mSv in a banana.

    1. So how much is a TSA body scan again?

      Seems like we’ll be measuring it in terms of cancer treatments for unshielded TSA agents.

  4. What’s the point of this chart if it is going to omit any hard numbers for banana phones? It dismisses them like some kind of joke or something.

  5. Glad that this got posted here for even wider viewing, I just finished reading it full size at xkcd.

    1. note to self…. remember to not keep the banana phone in my pants pocket.

      . You could always wrap it in tinfoil. That’ll stop beta radiation and impress lots of 70s and 80s rock fans.

  6. I’d like to get Maggie’s take on this before I decide how much credence to give it. No disrespect to Randall, his comics are awesome but MKB’s once-over would be worthwhile here. Also no disrespect to Sean either, but I don’t know if he’s been following Maggie’s incredible work on this very topic. She’s set a standard and it would be helpful to know how well this fits into that standard.

    1. whisper dog : “I’d like to get Maggie’s take on this before I decide how much credence to give it. No disrespect to Randall, his comics are awesome but MKB’s once-over would be worthwhile here. Also no disrespect to Sean either, but I don’t know if he’s been following Maggie’s incredible work on this very topic. She’s set a standard and it would be helpful to know how well this fits into that standard.”

      Ich auch <3 MKB, but Randall is no science-slouch. The sources for the data in his chart are all clearly referenced, and there is a reason that most of his cartoons have a very high geek quotient. Although they’re funny, the cartoons maths and science in his cartoons are invariably rock solid. In fact, they’re usually funny /because/ the maths or science is rock solid, which is no mean feat in itself. It also makes the cartoons quite engaging – often I’ll recognise that there is a punchline in a word or a sentence, but that I don’t know what the heck he’s talki ng about. 10 minutes and some google-fu later I’ll have learnt something and usually be giggling away :)


  7. Frankly said, that chart is quite a mess, especially since it doesn’t reflect on time-component sufficiently well.

    For example, you can’t seriously argue that a dental X-ray is magnitudes less dangerous than living a brick building, but that’s the message this diagram ultimately conveys.

    1. Frankly said, that chart is quite a mess, especially since it doesn’t reflect on time-component sufficiently well.


      1. I find it flawed, too.

        It was a little hard to read, though. Were exactly is the dose for living a year in Fukushima or Tokyo after the core melted and radioactive particles get into the atmosphere in large numbers?

        The point of most anti-nuclear activists isn’t that the radiation during normal operation is so high, but that it’s nearly uncontrollable if something goes wrong.

        I mean, a gun powder factory is perfectly safe when operationing within specs, but we don’t build them in cities, do we?

        1. Peter:

          > I mean, a gun powder factory is perfectly safe when operating within specs, but we don’t build them in cities, do we?

          Well …

          Also, I wouldn’t say that radiation is uncontrollable if anything goes wrong. Just as explosives, it is uncontrollable unless you set it up to be under control.

          In Fukushima they did so with the reactors in their containments(*). But they didn’t with the spent fuel pools, which are the main concern now. (Don’t ask me how anybody could be so stupid to put them right next to the reactor, outside of the containment building, 20-30m above ground. I slapped my head when I finally realized that …)

          (*) Hopefully. There is a picture of a plume that I can’t get out of my mind, because it looked almost like a shattered projectile after penetrating a wall. But given the radiation levels, the containments should be mostly intact (except for the leak in the suppression chamber).

          1. Actually, I was thinking of Enschede, when I wrote that. But I totally misremembered it with regards to being built away from the city.

            About uncontrollable: Technically, it’s controllable. Just look at Chernobyl. After some hysteria and sensible conern, you just declare an eclusion zone of some 60 km in diamater and ban all human life from it. :-)

            It’s probably a feasible technique for countries like the Ukraine with a population density 77/km^2 , but I’m not so sure about the feasibility of such a scheme in Germany (229/km2) or Japan (337.1/km2 – and I think much higher in practice) where something like this would displace millions.

            About stupidity: Well, these people operate under the assumption that the worst case will not happen. There’s a reasons why German law caps liability for atomic accidents and why most insurers will exclude atomic accidents from the terms of their contracts.

          2. My impression is those pools next to the reactors are the temporary ones for while they are in the removal process and then spent fuel is moved over to the dedicated shared pools. When you first pull something out of the oven you want put in on the nearest counter not walk across the block with it.

    2. For example, you can’t seriously argue that a dental X-ray is magnitudes less dangerous than living a brick building, but that’s the message this diagram ultimately conveys.

      Well you can take the ‘s’ off of ‘magnitudes’ for starters. The ratio he gives is 70/5 = 14x, closer to 10x (1 magnitude) than it is to 100x (2 magnitudes). As for “you can’t seriously argue …”, is this an opinion based on actual health physics, or just your gut feeling?

      1. Well, yes and no. Part of how radiation damage at low levels is measured is errors inflicted on your DNA. But your body has DNA repair mechanisms. In comparing the lower levels over a long timeframe (brick building) vs. the all at once (dental x-rays), it’s been argued that the lower levels over a longer timeframe offers the body more of a chance for recovery. Still controversial, look at the back and forth over mammography as an example.

        Recall an lecturer with an Australian accent talking about how he was working on assay of urine that measured metabolites of DNA repair, as a measure of damage. He was focused more on sun damage. There was a line in his leacture to the effect of “I was in the Outback for just a day, but I was pissing pyrmidine dimers for a week!” Guess you had to be there.

        1. There’s also a counter-argument that higher doses over short periods of time allow your body to recover, whereas a lower dose over a long period of time continues the DNA damage without allowing your body to repair it. Notably in this incident:


          the man that handled the radiation source and received a much higher overall dosage than his wife survived, whereas the wife passed away. She had received a lower dosage but over a longer span of time.

          1. Sad, but interesting wiki. There may have been an individual exception to the principle I mentioned, but it did also say:
            “Several people survived high doses of radiation. This is thought in some cases to be because the dose was fractionated. Given time, the body’s repair mechanisms will reverse cell damage caused by radiation. If the dose is spread over a long time period, these mechanisms can ameliorate the effects of radiation poisoning.” Thanks for citing it though.

    3. No, this chart sounds about right to me. Both of those things you just mentioned are also lower than the dose you get from natural potassium in the body.

      And I don’t think your complaint about the time component is relevant. It looks like Randall built the chart with cancer risk in mind, not radiation sickness.

      In fact, notice that he included the dose that causes radiation assuming in accumulated in a short amount of time. It’s the set of 40 red blocks in the red zone.

      Radiation sickness doesn’t even enter the picture for most of the chart. Hell, most of the green zone is below the “lowest one-year dose linked to cancer risk”.

      The chart looks fine to me.

    4. Anon:
      I think it’s entirely possible that living in a stone or brick house over time could cause more dangerous radiation exposure than a single dental X-ray, particularly if it’s poorly ventilated. Both granite and clays from many soil types contain traces of uranium, which decays into radon; that would tend to raise the indoor radon concentration above the base level which seeps in from the soil the house is built on. Radon is a potent carcinogen, particularly because it can be inhaled.

      If you look at the EPA site on radon risks, they now cite strong epidemiological evidence that radon exposure is the primary cause of over 20,000 cases of lung cancer per year in the US, second only to tobacco smoking.

      The intuition “seems obviously harmless” doesn’t always match up with the reality once it’s finally measured.

  8. One mistake – the timescale for the first entry.

    It is nonsensical to compare the dosage due to ‘Sleeping next to someone’ (for an undefined length of time) with ‘Living near a reactor for a certain length of time’ – one has a timescale and one doesn’t.

    That said – it’s a great diagram. I can’t agree with the previous comment that it’s a mess. It’s a diagram showing radiation DOSAGE.

    That’s what it shows. The complaint that radiation dosage isn’t the whole story and that a single diagram doesn’t explain everything is simply missing the point of the diagram.

    Heck – the diagram even starts by explaining this very point at the top!


  9. @Anon #13 — The problem is, it’s impossible to find a single timescale to compare them on. There is a note at the top that talks about how short-term and long-term doses are different.

    I worked with Randall on this and made http://people.reed.edu/~emcmanis/radiation.html as well, a different chart with more words and less pictures. The timescales are separate, which is nice, but it leads to something which has less comparative power.

  10. An order of magnitude increase in radiation dosage does not translate into “an order of magnitude more dangerous”. Both getting a dental x-ray and living in a brick building are both activities absolutely lacking in any sort of danger.

    1. It’s debatable where there’s a measurable risk. There has been suggested there’s a minimal increased risk of thyroid cancer with repeated dental x-rays. Compared to many other cancers, thyroid cancer tends to be a relatively treatable condition. Not x-raying and missing a dental abscess or tumour can of course also be dangerous.


  11. Last year our son, who was 12 months old at the time, had two head CT scans in one night. I winced when I saw the amount of radiation from one CT scan in the chart above. I expressed my concern to the doctors at the time about the amount of radiation he would be exposed to. The bottom line of what they told me was; ‘If he develops a tumor in 50 years, is it possible tonight will have had something to do with it? Yeah, maybe’. Obviously, not very reassuring, and nothing I read now is of any more help. Is there anyone out there with knowledge on the subject that can give me a little more insight, or at least make me feel a little less sick about it? Thank you.

    1. Please don’t feel too sick about it. As someone who has worked in the “radiation” biz, (not in a power plant but as a tech in a nuclear medicine production lab), I have a little experience. Docs and health-physicists are aware of the risk/reward problem. The physicians treating your son need images, the risks were weighed against the reward (diagnosing the problem).
      If you don’t trust the doctor’s opinion, that’s one thing, and you should do something about it. But if your son had a successful outcome, then perhaps your fear is a little premature.

      Don’t know if this is what you needed to hear, but best wishes. :)

    2. In a lifetime your son, like any person, will be exposed to many cancer sources. Natural radiation, many more x-rays, chemical cocktails in everyday food, heavy metals from polluted fish, oncoviruses, sunlight. There is no way to pinpoint the exact cause of a tumor in 50 years.

    3. Generally as regards CT scans, but especially to Anon @ #25 above…

      Maybe it’s just the individual doctors involved, but the doctors that I have dealt with in connection to CT scans have been pretty clear that they might involve some unknown but tiny increased risk of cancer, especially if one ends up having multiple scans over ones lifetime as is now likely. Certainly none of them have treated it as something you’d want to do just for the hell of it. But…

      How much is that cancer risk increase? If you go with the current guesses about linear increase of risk with radiation exposure, it would have to be down around a 1:2,500 or 0.04% increase in cancer risk, very possibly less. The risk of death from surgery, as an average of all causes, might be as high as 1:60, so any time a CT scan allows you to safely avoid an unnecessary surgery there’s something like a 40-fold reduction in risk.

      Particularly when my son had an abdominal CT scan to confirm whether his symptoms were really indicating appendicitis, the doctor made it very clear that we should treat the scan as a tiny but possible risk, to weigh against the risks of conducting surgery unnecessarily and of delaying surgery if it were necessary. (It was, he had it out, and was home and fine the next day.) I’ve had a couple CT scans, in the interest of early detection of any tumors which might have spread from a previous cancer – so I was weighing an unknown cancer risk against a definite cancer risk from possible metastasis. (Also in my case, there would have been a greater net risk as a side effect from the radiotherapy I had had.)

      If your son had two CT scans of his head, I would guess the doctors probably saw some indications of a head injury or cerebral hemorrhage, and needed to see if emergency treatment or surgery might be needed. (Yes, even toddlers can have strokes.) If that’s the case, or even if it was perhaps only a 1:10 chance, the risk of leaving it untreated would have been vastly higher than the minute risk from the CT scan.

      Reflecting on the whole question of risks, it seems to me the level of information which doctors are willing to give you now – if you ask them at the time – is vastly greater than when I was a kid.

  12. Hmmm, I need to make a list of people I want to give banana-phones next Christmas…

    (And if I really don’t like ’em, they will get one for their birthday’s too!)

  13. This is the state of the modern world:

    On one hand, the best researched and cited chart of radiation exposure is by a cartoonist, than by, say a respected media outlet.

    On the other hand it’s really easy to share this with everyone I know. (Not that they’ll care. Thy’re too busy eating bananas, buying potassium iodine pills and booking flights away from the west coast.)

  14. One thing this chart doesn’t show is the danger of particles of nuclear material getting into your body. Which is completely different than the kind of dosage that this chart describes.

    For instance, if plutonium is dispersed into the air by a non-nuclear explosion and you get a some particles into your lung. Then the alpha emitting plutonium particle is right next to your lung cells. Some studies show that it can increase the chance of cancer by 83%.

    It turns out that that Fukushima’s Plant #3 uses the MOX fuel which combines Plutonium with Uranium. And many of the fuel rods lying around in the cooling tanks have this plutonium mix.

    Plutonium is a major component of spent nuclear fuel rods. We have tons of it already sitting in pools of water outside of containment vessels at every single nuclear plant in the US.

    The danger from Nukes isn’t a working Nuclear Power Plant. Its from nuclear materials such as plutonium getting into the environment, particularly in particulate form. Plutonium has a 1/2 life of 25,000 years. It doesn’t bio degrade.

    Nuclear death is the death that keeps on giving. Once you inhale it and die from cancer, that plutonium is still there and could cause future cancers if re-released into the environment. Or if an explosion at a Nuke or a processing plant or an open pool of spent fuel rods releases plutonium in the air, it will keep get recycled thru the air via the rain water cycle.

    If we continue with nuclear power, we would be mining, moving, processing, using and storing 1000’s of tons of nuclear material per year. The chance for accidents or terrorist actions would be high enough to have many release events every decade.

    A few articles that convey the dangers of plutonium.

    Promotion of Pulmonary Carcinogenesis by Plutonium Particle aggregation following Inhalation of Plutonium239: http://www.jstor.org/pss/3577383

    Late-Occurring Pulmonary Pathologies Following Inhalation of Mixed Oxide (Uranium + Plutonium Oxide) Aerosol in the Rat http://journals.lww.com/health-physics/Abstract/2010/09000/Late_Occurring_Pulmonary_Pathologies_Following.10.aspx

    FACT SHEET: Risk from Plutonium in the Environment at Rocky Flats http://leroymoore.wordpress.com/2011/01/16/fact-sheet-risk-from-plutonium-in-the-environment-at-rocky-flats/

    The wikipedia article on Plutonium is pretty good. The last paragraph is pretty interesting:

    Metallic plutonium is a fire hazard, especially if the material is finely divided. In a moist environment, plutonium forms hydrides on its surface, which are pyrophoric and may ignite in air at room temperature. Plutonium expands up to 70% in volume as it oxidizes and thus may break its container.[99] The radioactivity of the burning material is an additional hazard. Magnesium oxide sand is probably the most effective material for extinguishing a plutonium fire. It cools the burning material, acting as a heat sink, and also blocks off oxygen. Special precautions are necessary to store or handle plutonium in any form; generally a dry inert gas atmosphere is required

  15. I’d love to have a full-sized print of this–I’m studying to be an interventional neuroradiologist, and it’d be cool to hang in my apartment.

  16. I hear again and again here (Tokyo) that the exposure from contaminated milk, spinach, etc is no more harmful than a CT scan.

    And of course, if necessary, we will all gladly have a CT scan.

    My biggest concern is what the effect on early foetal development is — I say this not only as a concern for pregnant Japanese women in general, but also for my own pregnant wife. Of course you would never send a pregnant woman through a CT scanner unless absolutely necessary.

    Can anyone point me toward real, non-hysterical, but also reliable (ie not the overly optimistic information the Japanese government is giving us) information about what the possible dangers are to early foetal development?

    1. Good luck with everything, according to this abstract of a review, if it
      s “just as much as a CT” there’s no detectable risk:


      “Prenatal doses from most properly done diagnostic procedures present no measurably increased risk of prenatal death, malformation, or impairment of mental development over the background incidence of these entities.”

  17. Great chart!!
    There might be missing a “All the doses in the red chart combined” piece in the yellow chart?

  18. I think he’s done a great job balancing the various issues there are in displaying this data. Some of the comments missed that it’s acknowledged that the doses are time-dependent. He doesn’t attempt to show time, he’s showing the full dose and mentions the amount of time where appropriate. You should be able to draw your own conclusions about how long a CT scan dose takes compared to, say, something marked “yearly”. Visualizing the time component would be interesting, but is essentially impossible to do without making the chart unreadable and decreasing its usefulness.

    The most important thing here is that the chart is constructed in such a way that an average person can look at it and understand essentially what it means and what the scale of various doses (including the threat from Fukushima) is. It provides perspective that anyone of reasonable intelligence should be able to understand.

    We all know it won’t really help most people, and that xkcd essentially preaches to the choir with this kind of thing, of course. Still very cool, and useful.

  19. one other problem is that the statistics cited for the fukushima levels are probably way too low. where is the data coming from? reliable sources in the know have put it *much* closer to chernobyl than banana’s.. just sayin.. where’s the data coming from?

  20. how many times a month is it safe to look at that chart? should i print it waterproof, then cool it in my fishtank?

  21. This chart would also be good for skittish dental X-ray patients (like me).
    “You don’t want your X-rays? Traveled in a plane lately.”

    Although, wait a second, is that dose per dental X-ray?
    If they do a series, they can do 15-18 X-rays on you …
    [scrambles back to chart to estimate dosage and reverts to paranoia]

    OK, no problem: that’s like a round-trip LA-Sydney flight.
    I can handle Australia-level X-rays…

  22. I think making people unafraid of radiation is a disservice to us all. Especially embryos, fetuses, pregnant women and children.

    They generally won’t even X-Ray a pregnant woman unless her life is at stake because it is so likely to cause the fetus to have birth defects or die.

    Ionizing radiation is known to cause harm in mammalian organisms. Deleterious effects of radiation include carcinogenicity, mutagenicity and organ system toxicity. As general rule, the sensitivity of a tissue to radiation is directly proportional to its rate of proliferation. Therefore, one could infer that the human fetus, because of its rapid progression from a single cell to a formed organism in nine months, is more sensitive to radiation than the adult. This inference is supported by the results of experiments in animal models, and experience with human populations that have been exposed to very high doses of radiation (atomic bombing victims). In humans, the major deleterious effects on the fetus include fetal wastage (miscarriage), teratogenicity (birth defects), mental retardation, intrauterine growth retardation and the induction of cancers (such as leukemia) that appear in childhood. Birth defects and mental retardation are the adverse effects which are of the most immediate concern for expectant mothers. Fortunately, not all exposures to ionizing radiation result in these outcomes. The risk to the fetus is a function of (a) gestational age at exposure and (b) the radiation dose.

    Early Gestation / First Trimester — At this point, the rate of fetal growth is very rapid and the fetus, as an organism, is at its most radiation-sensitive stage if fetal demise is taken as an end-point. The incidence of fetal wastage consequential to radiation exposure at this stage of gestation is not known, since (a) many women were never aware they were pregnant at the time of the exposure or miscarriage, and (b) the “background” rate of miscarriage is believed to be high (25 – 50 percent of conceptions). It is believed that radiation injury during early gestation is an “all-or-nothing” effect.

    Second Trimester — During this period, the overall growth rate of the fetus has slowed. However, the major organ systems are beginning to differentiate. From a standpoint of future development, the fetus is in its most sensitive stage. The incidence of gross congenital malformations and mental retardation are dose-related and appear to have thresholds; i.e. doses below which the incidence above “background” is not elevated.

    Third Trimester — Irradiation during this period may deplete cell populations at very high doses (over 50 rem), but will not result in gross organ malformations. http://www.safety.duke.edu/radsafety/fdose/fdrisk.asp

  23. what the heck?

    I had a whole long post typed up, and the only bit that got through was “Ich auch”? Gah. Not only is it a waste of time, but it also changes the meaning of my post :(

    Short version; MKB is teh bomb, but Randall is very, very scientifically literate. The sources for the data are all referenced. Geeks the world over pore over his cartoons in great detail, and only rarely find anything technically wrong with them. You can trust this chart (but then, that statement’s only useful if you trust /me/ … which was the point of your post anyway :D )

    1. There’s this thing called html. When you use the less than sign, you invoke it.

  24. Incidentally, this chart does have a time scale, but it’s implied rather than explicit. I mean … eating a banana takes how long? Sleeping next to someone is an activity that typically take how long? There might be some variation between you and I, but it can reasonably be taken to lie in the range of 6-10 hours, which doesn’t materially alter the dosage/hr. Airplane flight from NY to LA? Well, it’s not stated, but it does have a known, more-or-less fixed duration that’s fairly easy to find out. Various X-rays or CT scans? Again, the time duration might vary a little, but the total time is fairly well known and fairly short … and also irrelevant since it’s not like you’ll often be getting half of a CT scan, or quarter of an X-ray.

  25. Gotta love that even in a chart about radiation levels XKCD can’t resist throwing in a bit of a ‘my GIRLFRIEND’ :)

  26. From the about page on XKCD, regarding Randall:

    I’m just this guy, you know? I’m a CNU graduate with a degree in physics. Before starting xkcd, I worked on robots at NASA’s Langley Research Center in Virginia.

    …I think its safe to say the he’s more then just ‘cartoonist’. His opinion on this topic is more trustworthy then anything CNN has to say about it.

  27. Superb graphic on radiation levels.

    Ironically, FEMA recommends, as protection from nuclear radiation (or the aftermath of chemical or biological attacks or accidents), that we shelter in place at home and use duct tape and plastic sheeting to protect ourselves.

    How unbelievably silly. What’s needed is the Feds to fund development of these protective tiles so we could have truly safe, safe rooms.

    I mean, the Japanese were told to “not breath too much air” and to “not use the air conditioners” (it snowed the day before).


    We should contact our reps and demand something be done. It’s only a matter of time.

    1. I mean, the Japanese were told to “not breath too much air” and to “not use the air conditioners” (it snowed the day before).

      I didn’t catch that part of the PM’s speech, but lots of Japanese homes have heat pumps. Heat in the winter, cooling in the summer. Often generically referred to as ‘aircon’. As opposed to gas or electrical room heaters.

  28. Charts of this clarity and concision — regardless of their inevitable lack of utter comprehensiveness — would go much further towards defeating the risk posed by so-called “dirty bombs” than any million dollars of intelligence or law-enforcement: The chief risk posed by a dirty bomb is psychological; defeating fear in the face of radiation defeats the weapon itself.

  29. I haven’t had a chance to go over the numbers or sources yet, but I thought this comparison of death rate per TeraWatt-hour for various energy sources is interesting…


    Short form:
    source ….deaths/TW-h …% world energy
    Coal ……………. 161 …….. 26%
    Oil ……………….. 36 ……… 36%
    Natural Gas …….. 4 ……… 21%
    Solar (rooftop) … 0.44 …… 0.1%
    Wind ……………… 0.15 …… 1%
    Hydro ……………. 1.4 …….. 2.2%
    Nuclear ………… 0.04 ……. 5.9%

    So people falling from roofs installing solar panels is not insignificant.

    1. So people falling from roofs installing solar panels is not insignificant.

      I think the point here is that falling from a roof installing solar panels is a lot less dangerous (per TW hr) than working in a coal mine.

  30. OT:

    I made a translation to Spanish, but I’d like to keep the original font and style of the chart. I’d like to ask here if somebody is interested in helping with that.

    If you are, please contact me at guido () lava-amp. com

  31. Since there hasn’t been any actuall testing on humans on the effects of doses of radiation, it’s all still a guessing game isn’t it?

    My understanding of the storage of spent fuel rods in the US is that they are cooled for a period of time in uncontained pools untill they are cool enough to go into contained dry storage. Tons of spent rods are not just sitting around in the uncontained pool sipping beer the rest of their lives.

    Also, I know this is at a much lower level than Plutonium but there are several Gulf War 1(Desert Storm) Vets with chunks of depleted Uranium in their bodies. It’s a constant source of radiation, is it not? I wonder where that fall on the chart?

    1. There has been quite a lot of studies on the effects in humans – while it’d be “nicer” to work with known doses and well-designed experiments, the sum of information from studying those that have been exposed by accidents or attacks is fairly informative. (And that also goes for low exposures; you can correlate with the local background radiation, radon levels in their houses, etc – and some clear trends do fall out).

      As for the depleted uranium, I’d perhaps be more worried about the toxicology? It’s not an especially healthy metal even if you ignore the radioactive part.

      1. There are studies involving known doses. Radiation workers (nuclear plants, medical facilities, research use of radioisotopes) wear dosimeters at all times on the job, for a known chronic dose. Japan followed atomic bomb survivors for decades, and (since they know where they were when it happened) the acute dose can be accurately calculated.

        Very low doses- background rate, the occasional x-ray- are hard because the effect is so small, it would require a large study over a long timescale, with many thousands of people wearing dosimeters for many years. They’d need to account for background as people move around the world, and medical procedures, all of it. That’s really hard to do.

  32. And besides all that, I think nerd humour has been getting better over the past week. I’ve seen a plethora (trying not to say explosion) of fantastic nerd humour. Not that I’m calling you nerds or anything. And not that nerd humour wasn’t fresh and entertaining a while back.

  33. They should have used the elephant’s foot from Chernobyl on the chart. that thing is a constant 100 SV.

  34. This chart is flawed, it does not distinguish between milli sievert and micro sievert. Further more, not all items have the interval listed.
    For example, Maximum externals dose from Three Mile Island accident is shown as 1 mSV. Is it millisievert or microsievert (a 1000 time difference)? Is it 1 mSV per hour, per day, or what?

    1. Anon @ 79: “it does not distinguish between milli sievert and micro sievert.”

      The milli- (m) and micro- (μ) prefixes in the chart are the standard abbreviations used almost universally in the sciences, in a number of languages. They’re part of the SI system of units. The μ symbol in particular is not at all ambiguous; it is only used for millionths, never used for thousandths.

      Moreover, the second major rectangle in the chart contains an explanation of 1 mSv as 1000 μSv, just to the left of the 1 mSv number for Three Mile Island which you were commenting on.

  35. This ignores, as do almost all news stories, the radiation that enters the food chain and is ingested. The Cesium-137 from the spent fuel pools (which the US is overflowing with) is the greater danger than the reactors themselves.

    By limiting and distorting the argument to direct radiation, the public is misled about the very real disaster taking place right now and its full extent of environmental contamination.

  36. I guess I’ll just spell it out
    this article is giving out information that is dangerously wrong.
    From some well versed folks on the subject of dosages and how meaningless that concept is when discussing low level radiation as it is absorbed into the body, and sometimes bound to DNA where it can then sit around for years and passed onto the next generation.

    CERRIE Majority Report says
    Dose is meaningless

    Indeed, the actual concepts of absorbed dose become questionable, and sometimes meaningless, when considering interactions at the cellular and molecular levels.

    In other words, where hot or warm particles or Plutonium or Uranium are located in body tissue
    or where sequentially decaying radionuclides like Strontium 90 are organically bound (e.g. to DNA) “dose” means nothing.
    This is massively significant. Official radiation risk agencies universally quantify risk in terms of dose. If it means nothing the agencies know nothing and can give no valid advice.

    Their public reassurances fall to the ground. They can no longer compare nuclear industry discharges with the 2 millisieverts we get every year from natural radiation, or the cosmic rays you’d receive flying to Tenerife for a holiday.


  37. According to Hirose Takashi, numbers like those from this chart are misleading.

    From an interview with Hirose Takashi, broadcast by Asahi NewStar, 17 March, 20:00

    Hirose: All of the information media are at fault here I think. They are saying stupid things like, why, we are exposed to radiation all the time in our daily life, we get radiation from outer space. But that’s one millisievert per year. A year has 365 days, a day has 24 hours; multiply 365 by 24, you get 8760. Multiply the 400 millisieverts by that, you get 3,500,000 the normal dose. You call that safe? And what media have reported this? None. They compare it to a CT scan, which is over in an instant; that has nothing to do with it. The reason radioactivity can be measured is that radioactive material is escaping. What is dangerous is when that material enters your body and irradiates it from inside. These industry-mouthpiece scholars come on TV and what to they say? They say as you move away the radiation is reduced in inverse ratio to the square of the distance. I want to say the reverse. Internal irradiation happens when radioactive material is ingested into the body. What happens? Say there is a nuclear particle one meter away from you. You breathe it in, it sticks inside your body; the distance between you and it is now at the micron level. One meter is 1000 millimeters, one micron is one thousandth of a millimeter. That’s a thousand times a thousand: a thousand squared. That’s the real meaning of “inverse ratio of the square of the distance.” Radiation exposure is increased by a factor of a trillion. Inhaling even the tiniest particle, that’s the danger.

    Yoh: So making comparisons with X-rays and CT scans has no meaning. Because you can breathe in radioactive material.
    Hirose: That’s right. When it enters your body, there’s no telling where it will go. The biggest danger is women, especially pregnant women, and little children. Now they’re talking about iodine and cesium, but that’s only part of it, they’re not using the proper detection instruments. What they call monitoring means only measuring the amount of radiation in the air. Their instruments don’t eat. What they measure has no connection with the amount of radioactive material. . . .

    Yoh: So damage from radioactive rays and damage from radioactive material are not the same.
    Hirose: If you ask, are any radioactive rays from the Fukushima Nuclear Station here in this studio, the answer will be no. But radioactive particles are carried here by the air. When the core begins to melt down, elements inside like iodine turn to gas. It rises to the top, so if there is any crevice it escapes outside.

    If this is true, we’re being lied to.

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