The main threat to DNA is the occasional Reactive Oxidant Species (ROS). These are chemical radicals naturally produced by the oxidation of reductants (sugars etc.) in every animal cell. That oxidation provides energy, but ROS is occasionally released by accident. That's why we have anti-oxidants - to put out the 'fire-like mayhem' caused by ROS. At rest ROS is thought to cause about 10x the DNA damage of background radiation. Vigorous exercise increases the damage rate much more. It makes no difference how DNA gets damaged. The effect of DNA damage caused by ionizing radiation and ROS is the same.
Most damage happens to other cell proteins but as we know, DNA damage can cause long term problems. Fortunately, the double helix structure of DNA enables single strand breaks to get repaired quite quickly by the cell. Most double breaks take longer to repair by more complex cell processes. Where damaged DNA cannot be repaired the whole cell is sacrificed by apoptosis (immune response). Cancer cells develop in our bodies all the time and it is only as we age that our immune system weakens, raising the risk of developing cancer.
So yes, in an era where emissions from energy systems threaten mass extinction from Earth's climate, which is now warming at least 25x the warming rate that caused the worst mass extinction in geological history (End Permian or Great Dying), it would be laughable if it wasn't so sad that ALARA is used by misinformed ideologues to increase the cost of nuclear power.
Radioactive substances exist in all our food, our clothes, the ground, the structure of buildings, and the air - especially near coal plants, which emit uranium in their smoke. If you want to minimise the radiation you receive you should avoid go out on sunny days, and you should keep away from people and animals because they all have radioactive substances in their bodies. Carbon dating experts consider ideologues who declare themselves a radiation free zone 'in serious trouble': It means they must have dead at least 50,000 years.
> In other areas of our lives, this assumption would seem obviously wrong. For example, the cumulative harm model applied to alcohol would say that drinking a glass of wine once a day for a hundred days is equivalent to drinking one hundred glasses of wine in a single day. Or that a jogger who ran a mile a day for a month was putting her body under greater strain than one who ran a marathon in a day. We recognise that the human body is capable of repairing damage and stress done to it over time.
This is a false, harmful equivalence. None of the parallels you suggest involve *directly mutating your DNA*! There is *no* safe radiation level, and Linear No Threshold is accurate!
The problem, as you suggest elsewhere in your great piece, is ALARA, which chases marginal (but real!) improvements at massive cost.
Other things that 'directly mutate your DNA' include breathing oxygen, eating food, and sunlight exposure - why are the kinds of low levels we're talking about in this piece any different?
Thanks for replying! That's a great point and I agree - often our repair mechanisms are sufficient to combat the damage ionising radiation (and carcinogens, and oxygen) does to our DNA.
However, this does not mean the damage is not cumulative, in a way that running a mile a day is not! For instance, running a mile a day for a decade makes you fitter, but spending an hour a day in bright sunlight without sunscreen increases your overall chance of skin cancer! (Of course, you also get benefits like vitamin D, but the genetic damage is still present).
I agree with your underlying point that the marginal benefits of reducing radiation are not worth the ridiculous cost, but my original comment took issue with the false equivalence between radiation and alcohol or exercise.
Is living in North Dakota too dangerous for humans? DNA damage is happening all the time, but we keep fixing it. When the repair process is overwhelmed then bad things happen.
The habitable zone of the Earth does not include North Dakota 😂
But yes you're right! We can repair some damage, I guess my point is that the repair process for DNA is much slower and less robust than that for muscles or our liver, and so I don't think the analogy to alcohol or exercise is appropriate, even as an extreme example
I agree with your point regarding the cumulative nature of radiation exposure.
I think the author should have addressed his point using a different approach, one that looked at the cost of reducing risk as much as possible vs the benefit of doing so.
Perhaps a useful analogy would look at some common activity like traveling in an automobiles.
Assuming an exposure of 0.0001 mSv per year, the increased risk of cancer or other health effects would be extremely small, likely on the order of 1 in 100 million or less.
The risk of fatality in driving an automobile in the US is about 18,000 per year per 100 million. Let's use that, although a better measure might be the risk of injury, which, I suspect would be several times as high.
I suspect that we could add radar, computer controls, rebuild roads and bridges, add flotation, large crush zones, require helmets and fireproof suits, limit speeds to something like 20 MPH, figure out how to keep pedestrians and cars separate, etc. etc. etc. and still not get the levels of safety to anything near 1 injury per 100 million drivers. The cost would be extreme. Cars might cost an extra hundred thousand bucks... the other costs would be incredible.
But, people are completely happy to drive. Over 200 million of us do almost every day.
The question then becomes, at what point do we as a society believe it becomes unreasonable to burden business (and therefore society) with improvements in safety that are not measurably different from zero.
You’ve really hit the nail on the head when it comes to why it is so expensive to get anything built in the West. The levels of regulation that are, in isolation, admirable quickly become a burden which prohibits us from doing anything.
I served as secretary to UK govt. sci. advisory Committee Examining Radiation Risk from Internal Emitters (CERRIE); am now current member Irish Govt. Radiation Protection Advisory Committee (RPAC) - I can say that this article is bad science. All national, international radiation protection institutions and organisations are clear that there is no safe dose of radiation. It's just a thing called science.
Thing is, there is a clear scientific radiation protection consensus/agreement regards LNT. Quite simply, there is no safe dose. Also, the science gets complex regards internal - genomic instability, bystander effect, and so on.
The piece does in fact mention the international regulatory consensus - I just think it has more to do with inertia, and the difficulty of proving a negative. The regulatory consensus also masks a growing chorus of scientists who don't agree with it!
In a hypothetical world, where we were designing an international radiation protection regime from scratch with the evidence that we have now, do you think we would pick LNT?
Arguing against the LNT consensus is a bit like being in denial of the scientific climate consensus. I guess it's OK for some to keep on questioning - but scientific facts are still scientific facts.
That's an absurd comparison - our understanding of climate change is built on empirical models that are tested and updated across a wide range of disciplines. LNT is a conservative risk assessment tool that the ICRP specifically says lacks predictive power. The consensus levels in the scientific community between the two also vary wildly.
In addition, even the NRC admits that: "The NRC acknowledges the difficulties inherent in determining the amount of damage to the human body caused by low doses of radiation. The NRC, however, does not use the LNT model to assess the actual risk of low dose radiation. Instead, the NRC uses the LNT model as the basis for a regulatory framework that meets the “adequate protection” standard of the Atomic Energy Act of 1954, as amended (AEA). "
Even the NRC admits that the science isn’t completely valid: This whole document is full of statements saying that it is rather hard to actually prove the “no safe dose” theory, for example "The NRC acknowledges the difficulties inherent in determining the amount of damage to the human body caused by low doses of radiation. The NRC, however, does not use the LNT model to assess the actual risk of low dose radiation. Instead, the NRC uses the LNT model as the basis for a regulatory framework that meets the “adequate protection” standard of the Atomic Energy Act of 1954, as amended (AEA). "
It is not only nuclear power that is affected by these obscenely expensive requirements. The lower Thames tunnel cost over £400 million before a spade entered the ground. There must be a gang of bureaucrats out there somewhere making a living requiring Bat Tunnels on the motorways and filtration systems on nuclear developments that reduce our exposure to less danger than eating a banana. Time this entire level of scrutiny was checked.
It’s impossible to hand wave away the LNT even if we know it’s obviously not true (exposing yourself to more radiation on a flight is perfectly fine) because 1) nobody knows what that threshold is, and 2) it’d be incredibly difficult, if not impossible, to determine what it is. Nick Touran details an alternative in point 6 here:
I think Nick's potential policy fix has merit, although I disagree with him on how robust INWORKS is as evidence for LNT. I'm not one of those people who makes challenging LNT their identity (and have deliberately avoided the hormesis wars...), but I think 'noble lies' are bad and that if we put our mind to it, we probably could do better. It could be setting a threshold (even if it is on the conservative side) below which it is very hard to determine harm, or some form of concave up line (which acknowledges that higher acute doses do more complex damage, as we already do in radiotherapy planning)
I don’t think the data matters since this is a policy question, not a science one. With a third of our radiation exposure being non-background, we’re obviously okay with some extra risk. Either defining a number with an exemption criteria or establishing a process for choosing a number would be a good thing. Well defined constraints can be preferable than wide flexibility. You’d likely need Congress to establish this though. This administration has still not learned that EOs are not laws
Suppose we (hypothetically) totally accepted the linear no threshold model. And then we applied sensible utilitarian reasoning, with a price-per-life comparable to other industries.
If LNT was totally true, would the health effects from nuclear pollution be comparable to that of coal on a per-kilowatt basis?
I suspect the main failure here is not the belief in a very small risk from small amounts of radiation, but a determination to make the risks from radiation as small as possible, regardless of the tradeoffs.
Nonlinearity at low doses, beyond that which is statistically discernible, could imply milder health effects if there's a threshold beyond which tiny amounts of radiation don't affect health. But reality could be mean. A nonlinear marginal damage curve could imply *worse* health effects over certain ranges, relative to the the linear model. Linear no-threshold (LNT) seems to me to be entirely reasonable, given the science that existed up to, say, 1990. It was certainly backed by scientific consensus, though far from universally.
But ALARA (as low as reasonably achievable) doesn't necessarily follow from LNT. Burning coal releases radiation into the environment. If we apply LNT to radiation absent strong data to the contrary, we should apply a broadly similar conceptual framework to other pollutants. Perhaps a better approach would be, "Risk minimization relative to the alternatives". We wouldn't *quite* arrive at a straightforward cost/benefit analysis from that, but at least it would acknowledge that a forgone nuclear power plant implies greater coal, oil, and natural gas emissions.
I think it's unlikely that risk is linear - for example, in cancer treatment, we use a nonlinear, concave-up curve to model tumour cell kill and tissue response. This is because we believe that higher doses cause more complex damage that it is harder for cells to repair. This is why treatment is done in small doses, rather than one big blast. I find it interesting that in these high stakes settings, we don't use LNT...
When it comes to the comparatively low doses we're dealing with around nuclear power, I would be surprised if there was some kind of supralinear dose-response curve at low doses, because i) the the empirical evidence is there (we've seen enough populations exposed to elevated levels of radiation for a long time I think it would have shown up) ii) it doesn't account for DNA repair and cellular defence responses.
I'm sympathetic to your last point, but I think ALARA probably was an inevitable consequence of LNT, given the state of our biological knowledge at the time. Thinks like DSB repair weren't known to scientific committees in the 1950s etc.
Re: coal - I'm sure an anti-nuclear person would argue that radiation from coal is uncontrolled and diffuse, versus the highly concentrated, acute doses you could get if containment in a nuclear facility failed. But yes, I agree that judging these kinds of risks in isolation from each other is pointless.
> but I think ALARA probably was an inevitable consequence of LNT, given the state of our biological knowledge at the time.
It might be politically inevitable, but it's also stupid. The right answer is to go do the maths of utilitarianism.
Let's consider an asteroid risk LNT. Doubling your sky-exposure (time not in a bunker) doubles your chance of being killed by asteroid impact. This is clearly a linear relation. 2x as much time on the earths surface = 2x as much chance of dying by asteroid.
So ALARA would recommend spending as little time outside an asteroid-proof bunker as "reasonably achievable".
But the chance of asteroid impact is basically 0, so we mostly ignore it and get on with life.
Great article - thanks.
The main threat to DNA is the occasional Reactive Oxidant Species (ROS). These are chemical radicals naturally produced by the oxidation of reductants (sugars etc.) in every animal cell. That oxidation provides energy, but ROS is occasionally released by accident. That's why we have anti-oxidants - to put out the 'fire-like mayhem' caused by ROS. At rest ROS is thought to cause about 10x the DNA damage of background radiation. Vigorous exercise increases the damage rate much more. It makes no difference how DNA gets damaged. The effect of DNA damage caused by ionizing radiation and ROS is the same.
Most damage happens to other cell proteins but as we know, DNA damage can cause long term problems. Fortunately, the double helix structure of DNA enables single strand breaks to get repaired quite quickly by the cell. Most double breaks take longer to repair by more complex cell processes. Where damaged DNA cannot be repaired the whole cell is sacrificed by apoptosis (immune response). Cancer cells develop in our bodies all the time and it is only as we age that our immune system weakens, raising the risk of developing cancer.
So yes, in an era where emissions from energy systems threaten mass extinction from Earth's climate, which is now warming at least 25x the warming rate that caused the worst mass extinction in geological history (End Permian or Great Dying), it would be laughable if it wasn't so sad that ALARA is used by misinformed ideologues to increase the cost of nuclear power.
Radioactive substances exist in all our food, our clothes, the ground, the structure of buildings, and the air - especially near coal plants, which emit uranium in their smoke. If you want to minimise the radiation you receive you should avoid go out on sunny days, and you should keep away from people and animals because they all have radioactive substances in their bodies. Carbon dating experts consider ideologues who declare themselves a radiation free zone 'in serious trouble': It means they must have dead at least 50,000 years.
> In other areas of our lives, this assumption would seem obviously wrong. For example, the cumulative harm model applied to alcohol would say that drinking a glass of wine once a day for a hundred days is equivalent to drinking one hundred glasses of wine in a single day. Or that a jogger who ran a mile a day for a month was putting her body under greater strain than one who ran a marathon in a day. We recognise that the human body is capable of repairing damage and stress done to it over time.
This is a false, harmful equivalence. None of the parallels you suggest involve *directly mutating your DNA*! There is *no* safe radiation level, and Linear No Threshold is accurate!
The problem, as you suggest elsewhere in your great piece, is ALARA, which chases marginal (but real!) improvements at massive cost.
Other things that 'directly mutate your DNA' include breathing oxygen, eating food, and sunlight exposure - why are the kinds of low levels we're talking about in this piece any different?
But I'm glad you liked the rest of the piece!
Thanks for replying! That's a great point and I agree - often our repair mechanisms are sufficient to combat the damage ionising radiation (and carcinogens, and oxygen) does to our DNA.
However, this does not mean the damage is not cumulative, in a way that running a mile a day is not! For instance, running a mile a day for a decade makes you fitter, but spending an hour a day in bright sunlight without sunscreen increases your overall chance of skin cancer! (Of course, you also get benefits like vitamin D, but the genetic damage is still present).
I agree with your underlying point that the marginal benefits of reducing radiation are not worth the ridiculous cost, but my original comment took issue with the false equivalence between radiation and alcohol or exercise.
Is living in North Dakota too dangerous for humans? DNA damage is happening all the time, but we keep fixing it. When the repair process is overwhelmed then bad things happen.
The habitable zone of the Earth does not include North Dakota 😂
But yes you're right! We can repair some damage, I guess my point is that the repair process for DNA is much slower and less robust than that for muscles or our liver, and so I don't think the analogy to alcohol or exercise is appropriate, even as an extreme example
I agree with your point regarding the cumulative nature of radiation exposure.
I think the author should have addressed his point using a different approach, one that looked at the cost of reducing risk as much as possible vs the benefit of doing so.
Perhaps a useful analogy would look at some common activity like traveling in an automobiles.
Assuming an exposure of 0.0001 mSv per year, the increased risk of cancer or other health effects would be extremely small, likely on the order of 1 in 100 million or less.
The risk of fatality in driving an automobile in the US is about 18,000 per year per 100 million. Let's use that, although a better measure might be the risk of injury, which, I suspect would be several times as high.
I suspect that we could add radar, computer controls, rebuild roads and bridges, add flotation, large crush zones, require helmets and fireproof suits, limit speeds to something like 20 MPH, figure out how to keep pedestrians and cars separate, etc. etc. etc. and still not get the levels of safety to anything near 1 injury per 100 million drivers. The cost would be extreme. Cars might cost an extra hundred thousand bucks... the other costs would be incredible.
But, people are completely happy to drive. Over 200 million of us do almost every day.
The question then becomes, at what point do we as a society believe it becomes unreasonable to burden business (and therefore society) with improvements in safety that are not measurably different from zero.
Great article!
You’ve really hit the nail on the head when it comes to why it is so expensive to get anything built in the West. The levels of regulation that are, in isolation, admirable quickly become a burden which prohibits us from doing anything.
I served as secretary to UK govt. sci. advisory Committee Examining Radiation Risk from Internal Emitters (CERRIE); am now current member Irish Govt. Radiation Protection Advisory Committee (RPAC) - I can say that this article is bad science. All national, international radiation protection institutions and organisations are clear that there is no safe dose of radiation. It's just a thing called science.
Good to know that there are never any disagreements between practitioners of The Science - thanks for putting my mind at rest!
Thing is, there is a clear scientific radiation protection consensus/agreement regards LNT. Quite simply, there is no safe dose. Also, the science gets complex regards internal - genomic instability, bystander effect, and so on.
The piece does in fact mention the international regulatory consensus - I just think it has more to do with inertia, and the difficulty of proving a negative. The regulatory consensus also masks a growing chorus of scientists who don't agree with it!
In a hypothetical world, where we were designing an international radiation protection regime from scratch with the evidence that we have now, do you think we would pick LNT?
Arguing against the LNT consensus is a bit like being in denial of the scientific climate consensus. I guess it's OK for some to keep on questioning - but scientific facts are still scientific facts.
That's an absurd comparison - our understanding of climate change is built on empirical models that are tested and updated across a wide range of disciplines. LNT is a conservative risk assessment tool that the ICRP specifically says lacks predictive power. The consensus levels in the scientific community between the two also vary wildly.
https://www.federalregister.gov/documents/2021/08/17/2021-17475/linear-no-threshold-model-and-standards-for-protection-against-radiation
In addition, even the NRC admits that: "The NRC acknowledges the difficulties inherent in determining the amount of damage to the human body caused by low doses of radiation. The NRC, however, does not use the LNT model to assess the actual risk of low dose radiation. Instead, the NRC uses the LNT model as the basis for a regulatory framework that meets the “adequate protection” standard of the Atomic Energy Act of 1954, as amended (AEA). "
If there is "no safe dose of radiation", then how does life around Chernobyl exist?
https://knowablemagazine.org/content/article/food-environment/2022/scientists-cant-agree-about-chernobyls-impact-wildlife
https://www.loe.org/shows/segments.html?programID=16-P13-00018&segmentID=4
Here's another source. Neither of these sources say anything close to "all the evidence we've found is that radiation is always bad"
Apparently some random sources know more than all national and international radiation protection regulatory institutes and organisation ...
https://www.federalregister.gov/documents/2021/08/17/2021-17475/linear-no-threshold-model-and-standards-for-protection-against-radiation
Even the NRC admits that the science isn’t completely valid: This whole document is full of statements saying that it is rather hard to actually prove the “no safe dose” theory, for example "The NRC acknowledges the difficulties inherent in determining the amount of damage to the human body caused by low doses of radiation. The NRC, however, does not use the LNT model to assess the actual risk of low dose radiation. Instead, the NRC uses the LNT model as the basis for a regulatory framework that meets the “adequate protection” standard of the Atomic Energy Act of 1954, as amended (AEA). "
It is not only nuclear power that is affected by these obscenely expensive requirements. The lower Thames tunnel cost over £400 million before a spade entered the ground. There must be a gang of bureaucrats out there somewhere making a living requiring Bat Tunnels on the motorways and filtration systems on nuclear developments that reduce our exposure to less danger than eating a banana. Time this entire level of scrutiny was checked.
It’s impossible to hand wave away the LNT even if we know it’s obviously not true (exposing yourself to more radiation on a flight is perfectly fine) because 1) nobody knows what that threshold is, and 2) it’d be incredibly difficult, if not impossible, to determine what it is. Nick Touran details an alternative in point 6 here:
https://whatisnuclear.com/news/2025-05-23-regulatory-reforms-nuclear-wants.html
I think Nick's potential policy fix has merit, although I disagree with him on how robust INWORKS is as evidence for LNT. I'm not one of those people who makes challenging LNT their identity (and have deliberately avoided the hormesis wars...), but I think 'noble lies' are bad and that if we put our mind to it, we probably could do better. It could be setting a threshold (even if it is on the conservative side) below which it is very hard to determine harm, or some form of concave up line (which acknowledges that higher acute doses do more complex damage, as we already do in radiotherapy planning)
I don’t think the data matters since this is a policy question, not a science one. With a third of our radiation exposure being non-background, we’re obviously okay with some extra risk. Either defining a number with an exemption criteria or establishing a process for choosing a number would be a good thing. Well defined constraints can be preferable than wide flexibility. You’d likely need Congress to establish this though. This administration has still not learned that EOs are not laws
Suppose we (hypothetically) totally accepted the linear no threshold model. And then we applied sensible utilitarian reasoning, with a price-per-life comparable to other industries.
If LNT was totally true, would the health effects from nuclear pollution be comparable to that of coal on a per-kilowatt basis?
I suspect the main failure here is not the belief in a very small risk from small amounts of radiation, but a determination to make the risks from radiation as small as possible, regardless of the tradeoffs.
Oh dear. There is a clear global scientific regulatory consensus for LNT. To be in denial of that fact seems rather 'heroic'. Tin hat's on !
Nonlinearity at low doses, beyond that which is statistically discernible, could imply milder health effects if there's a threshold beyond which tiny amounts of radiation don't affect health. But reality could be mean. A nonlinear marginal damage curve could imply *worse* health effects over certain ranges, relative to the the linear model. Linear no-threshold (LNT) seems to me to be entirely reasonable, given the science that existed up to, say, 1990. It was certainly backed by scientific consensus, though far from universally.
But ALARA (as low as reasonably achievable) doesn't necessarily follow from LNT. Burning coal releases radiation into the environment. If we apply LNT to radiation absent strong data to the contrary, we should apply a broadly similar conceptual framework to other pollutants. Perhaps a better approach would be, "Risk minimization relative to the alternatives". We wouldn't *quite* arrive at a straightforward cost/benefit analysis from that, but at least it would acknowledge that a forgone nuclear power plant implies greater coal, oil, and natural gas emissions.
I think it's unlikely that risk is linear - for example, in cancer treatment, we use a nonlinear, concave-up curve to model tumour cell kill and tissue response. This is because we believe that higher doses cause more complex damage that it is harder for cells to repair. This is why treatment is done in small doses, rather than one big blast. I find it interesting that in these high stakes settings, we don't use LNT...
When it comes to the comparatively low doses we're dealing with around nuclear power, I would be surprised if there was some kind of supralinear dose-response curve at low doses, because i) the the empirical evidence is there (we've seen enough populations exposed to elevated levels of radiation for a long time I think it would have shown up) ii) it doesn't account for DNA repair and cellular defence responses.
I'm sympathetic to your last point, but I think ALARA probably was an inevitable consequence of LNT, given the state of our biological knowledge at the time. Thinks like DSB repair weren't known to scientific committees in the 1950s etc.
Re: coal - I'm sure an anti-nuclear person would argue that radiation from coal is uncontrolled and diffuse, versus the highly concentrated, acute doses you could get if containment in a nuclear facility failed. But yes, I agree that judging these kinds of risks in isolation from each other is pointless.
Thanks for reading!
> but I think ALARA probably was an inevitable consequence of LNT, given the state of our biological knowledge at the time.
It might be politically inevitable, but it's also stupid. The right answer is to go do the maths of utilitarianism.
Let's consider an asteroid risk LNT. Doubling your sky-exposure (time not in a bunker) doubles your chance of being killed by asteroid impact. This is clearly a linear relation. 2x as much time on the earths surface = 2x as much chance of dying by asteroid.
So ALARA would recommend spending as little time outside an asteroid-proof bunker as "reasonably achievable".
But the chance of asteroid impact is basically 0, so we mostly ignore it and get on with life.
Oh dear ...