Chatterbox's friend Gregg Easterbrook, author of A Moment on the Earth: The Coming Age of Environmental Optimism (click here to buy the book) and Beside Still Waters: Searching for Meaning in an Age of Doubt (click here to buy the book), and a senior editor at the New Republic , has a quarrel with Chatterbox's item about radon pilgrims (see "Let Us Now Praise Phony Cures").
It's true that radon exposure in homes is dangerous, if above the 4 picocurie/liter level established by the EPA and the National Research Council. But ... it's dangerous because exposure is continuous. Radon mine exposure is brief. Being in a home with radon is like smoking a cigarette constantly. On the other hand, if you smoke a cigarette a couple times per year, it's not going to affect you. Put another way, if you took Tylenol 3 continuously, every day, every hour, it would play hell with your body, as would almost any other medicine. If you take it a couple times a year after spraining an ankle, it's helpful.
That's the difference between radon in the home and radon in "health" mines. Health mines may be promoted as quackery, but they're unlikely to be dangerous (except to workers, as you note, owing to continuous effects).
A mystery of biology is that so far it seems that very low levels of radiation exposure (only very low levels, but then many medicines are beneficial only at very low levels) do seem to have a positive effect. Rosalyn Yalow, a Nobel Prize biologist, has done the most work in this field, and she's published quite a bit on the perplexing point that very low exposure to radiation makes people more healthy, not less.
For example, Colorado has lower cancer rates than California. Because of its altitude, which means naturally high solar radiation exposure, and its (low) levels of radon owing to its natural bedrock, Colorado residents experience about 4 times the natural background radiation of Californians, yet they get less cancer.
Nobody knows if the association between very low levels of radiation and health benefits is an artifact of something else or is biological, because no one has found a mechanism by which radiation benefits cells. And all respectable researchers are wary of suggesting to the nuts out there that they ought to blast themselves with uranium.
But, Chatterbox, there is serious science suggesting that little bits of radiation may be good. Comparing home radon to the perhaps-nutty idea of radon mines isn't the right comparison; it's like comparing drug addiction to occasional medicinal use.
It's true, as medical experts always say, the dose makes the poison. Chatterbox probably should have said that in his item. But in this case it's hard to know what the dose is. How many visits does the typical radon pilgrim make? Conceivably, even one mine visit might cause harm if the radiation level is too high; and because levels fluctuate, it's hard to know what any individual is being exposed to.
Chatterbox must admit ignorance, however, of the research on the possibly beneficial effects of low-level radiation. He is not ready to move to Colorado, but will keep an eye on this topic from now on.
Not to belabor, but it's very unlikely one mine visit could cause health damage, although I suppose technically you can't rule it out. Philip Abelson of the American Association for the Advancement of Science made his reputation studying the health effects of radon on uranium miners of the 1940s and 1950s, and everything he found was long-term. There's a dispute in radiation science about whether single exposures can trigger mutations that cause harm, or whether long-term exposure is required. But for single-exposure harm the kinds of things in question are the "prompt" radiation of a nuclear blast (a clear yes) or the radiation from high-level reactor waste (unclear). In either case you are talking about energies many orders of magnitude higher than radon.
I have to get back to work now.