According to "The Myth of Plutonium Toxicity" by Bernard L. Cohen:

Plutonium is constantly referred to by the news media as ``the most toxic substance known to man.'' Ralph Nader has said that a pound of plutonium could cause 8 billion cancers, and former Senator Ribicoff has said that a single particle of plutonium inhaled into the lung can cause cancer.

The book sources the quote as coming from:

  • R. Nader, speech at Lafayette College (Spring 1975).

Another source states that he said this in a debate with radiation pioneer Ralph Lapp:

For example, one day consumer activist Ralph Nader was debating radiation pioneer Ralph Lapp. Nader stated that a pound of plutonium could kill every human being on Earth. One could picture a one-pint jar of the stuff spilling on the ground and its dea dly vapors spreading until all life was obliterated. That's what Nader's statement means in the common-sense real world. But Lapp put the statement in its proper context by replying: "So could a pound of fresh air, Ralph." Now how can that be? We've been repeatedly told that plutonium is the deadliest substance known. And we know that fresh air is literally the breath of life. What's going on here? Nader's statement was not actually a lie; he was just trying to make us think that a hypothetical conjecture was a real-world problem. He's saying that the lethal dose of plutonium is a five-billionth of a pound. It's really several thousand times larger, but even if Nader were correct, the only way you could actually kill the world's 5 billion people with just one pound would be to line them up and have a trained physician inject into each person just the toxic amount of plutonium-no more or there wouldn't be enough to go around. It would have to be in a fine aerosol mist, or it wouldn't be lethal, and it would have to go directly into the lung. Then we would have to wait several decades, protecting the individual from other life-threatening influences such as cars, smoking, and malnutrition, until he or she died of lung cancer, because plutonium poses no other health threat.

Context can make a huge difference in what people actually mean, so I wonder if Ralph Nader has actually claimed that a pound of plutonium could cause 8 billion cancer deaths, and, if so, if context would indicate whether he means it in the way it is interpreted.

Did Ralph Nader claim that a pound of plutonium could cause 8 billion cancers?

Question inspired by: Is plutonium the most toxic substance known to man?

  • 2
    Earth's human population in 1975 was about 4 billion, FYI. Commented Sep 21, 2016 at 16:07

2 Answers 2


It is a common figure of speech to say [small amount] of toxin could kill [large amount] people. (Examples: 1, 2) It is an emotive demonstration of the toxicity, but it openly ignores the complexity of the delivery mechanism - an assumption Rockwell scoffs at.

What is more relevant than the figure of speech used to describe the toxicity, is the underlying level of toxicity claimed:

He's saying that the lethal dose of plutonium is a five-billionth of a pound.

While I don't have a transcript of his March 11, 1975 speech, I did find an article Nader wrote about two weeks later (Source: Nader.org):

Any use of plutonium, a tiny 0.2 micrograms of which has given lung can­cer to animals, must be viewed with utmost caution.

There are 2,267,961,850 doses of 0.2 micrograms per pound - i.e. about 2 billion.


  • based on this article, rather than the cited speech,
  • assuming similar dosages will work on humans, as well as other animals,
  • ignoring the distribution mechanisms required to split the dosages up and apply them to the lungs of the humans:

Ralph Nader did suggest that the toxicity of Plutonium was high enough to cause over 2 billion cancers per pound.

This is lower than the quoted 8 billion, but shows Nader was making toxicity claims in the ball-park of the quote.

  • 2
    Any data on how much plutonium could be considered dangerous in humans is going to be tenuous at best because so few humans have actually been exposed to it and animal models can only take you so far. There is evidence to suggest that people can survive with detectable levels of plutonium in their bodies with no ill effects, though. The UPPU club (U P Pu, you pee plutonium) is a "club" whose members comprise of people with enough plutonium in their bodies for it to be detectable in their urine. fourmilab.ch/documents/reading_list/indices/book_596.html
    – GordonM
    Commented Jul 30, 2015 at 8:12
  • @GordonM: I agree; I explicitly noted that dosage equivalency (or at least similarity) between humans and lab animals as an assumption. I think it is fair to say that Nader intended for people to make that assumption, or he wouldn't have quoted that figure.
    – Oddthinking
    Commented Jul 30, 2015 at 9:38

According to LeHigh University Brown and White, Volume 36, No. 41, Tuesday, March 11, 1975, Nader introduced a two-day “Symposium on Nuclear Power Development and Society” at Lafayette, where he said:

Nader referred to nuclear power as a producer of deadly radioactive materials. Plutonium 239, while the "deadliest cancer producing agent ever produced by man," is "a prodigious product of the forthcoming breeder reactor," he said. Nader said production of plutonium is a major category of concern.

I could not confirm the 8 billion number.

  • When the statement was made, it would not have been 8 billion. Commented Sep 21, 2016 at 16:07

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