The following questions are reasonable to ask any strongly opinionated person worried about radiation exposure from Rocky Flats soil.   They may be used to roughly assess their credibility.

Questions and answers

Q: What makes plutonium special, in comparison say to natural radioactive substances?

A: Nothing, really.  It is artificial, but its radiation is no different than what comes from natural alpha-particle emitters.  It is unusual since it emits so few gamma rays that it cannot be detected by aerial surveys or easily by Geiger counters, so it gives very little “whole body” dose.

Q: How do you get exposed to plutonium? How close to you have to be?

A: Almost all health risk from plutonium is from high-energy alpha particles, which ionize molecules in cells.  Alphas have a range in air of a couple of inches and cannot penetrate skin.  Thus essentially all exposure comes by inhaling or swallowing dust from contaminated soil.

Q: If radiation causes cancer, why is it used to treat cancer?

A: Ionizing radiation is much more effective at killing cells than it is at inducing changes which lead to cancer. As with any substance, it is the dose that matters.  Radiation therapy is used when the chances of inducing a `second malignant neoplasm’ are very small in comparison to the expected medical benefit, at a rate of about 12.5% over 20 years for adolescents and young adults. The doses in radiation therapy are frequently 10,000 times higher than natural ‘background radiation’

Q: Can you give me an estimate of your yearly dose of radiation from natural background (cosmic rays, soil radioactivity)?
How much do you get from, say, a chest X-ray? Can you compare this with the dose you get from plutonium in one year?

Q.: Can you give me an estimate of a radiation dose delivered to a tumor for therapy? Can you give me an estimate of the minimum dose to your whole body needed to show negative health effects?

Tumor doses are in the range of 2-60 Sievert units.  Most radiation epidemiologists use 0.1 Sievert as the dose below which it is very hard to measure any negative health effect.

Q: What fraction of total Rocky Flats soil radioactivity comes from plutonium?

NIST soil standards clearly indicate this is less than 1%, or 2.5% if you focus on alpha emitting radioisotopes.

Can you give me an estimate of the range of say, alpha particles vs. gamma rays?

Alpha particles: a couple of inches; gamma rays: infinite range in empty space (like light), but hundreds of meters in air.