EDITORIAL: Radon, For Your Health… Part One
Ring-around the rosie, pocket full of posies,
Radon, radon, we all fall down!
— Traditional playground singing game, updated for 2017
When the scientists of the 14th century were faced with the cruel epidemic of the Black Death — the bubonic plague — they struggled to come up with medical treatments that would increase the chances of survival. There’s little evidence that doctors, in 1348, understood the connection between flea bites and onset of the disease — a connection that’s well accepted in 2017 — so medical science came up with a range of preventative measures and treatments that included:
1. Cooked onions;
3. Sitting in the sewers;
4. Fumigating the house with herbs;
5. Self-flagellation (flogging oneself with a whip, rod, switch or other painful object.)
Although we might look back on these treatments with a large measure of skepticism as to their effectiveness, they were endorsed by the scientific and religious leaders of the day, and embraced by the common folk. In spite of these medical procedures, however, the population of central Europe was decimated between 1348 and 1350, when maybe a third of the continent’s total population succumbed to the plague.
Which is a reminder that there’s good science… and there’s bad science. Although medicine and science have evolved somewhat since 1350, the situation remains true: some science is simply ‘bad science.’
Whether this situation currently holds regarding radon gas, I will allow you, the reader, to decide.
Here in America, many people hold the belief that radon gas — typically found in minute amounts inside people’s homes — is a leading cause of lung cancer. The main propagandist for this belief seems to be the federal government, via studies and recommendations published by the Environmental Protection Agency — the EPA — and a series of National Research Council reports on the “Biological Effects of Ionizing Radiation” (BEIR).
The subject of radon gas reared its head locally, last Wednesday, July 5, during a vote by the Archuleta Board of County Commissioners. At issue was a curious local regulation that allows homebuilders to waive a requirement written into the International Building Code — a requirement that builders must mitigate radon exposure in new residential construction. Recommendations in the IBC are typically adopted by county and town governments without any real research into the usefulness of those recommendations, nor into the financial cost.
In the case of radon mitigation, the typical assumption is… well, the EPA must know what they are talking about.
Here in Archuleta County, the 2006 IBC has been adopted, but a special waiver allowed homeowners to bypass the mitigation requirement by simply signing a consent form and filing it with the County Clerk. According to the owner of a local construction company, this has resulted in about 98 percent of new homes in Archuleta County applying for the waiver.
At last Wednesday’s BOCC meeting, the allowance for this waiver was repealed. So starting on Thursday, and for the time being, every new building permit in the unincorporated county will need to include radon mitigation in its plans.
Radon, as most people know, is a relatively heavy, odorless, radioactive gas released in minute amounts from rocks containing uranium or radium… like, for example, the rocks in Archuleta County, and in many other places around the country. Because radon is radioactive, and because radioactivity has been linked to various cancers — such as lung cancer — the EPA has established a recommended limit to the amount of radon gas that should be allowed inside an American home:
4 picoCuries per liter of air.
Here’s a map showing, county by county, the relative amount of radon-caused radiation we might expect to find inside a dwelling, courtesy of the U.S. Department of Energy. The dark blue shows counties where radon is almost never found at levels higher than 4 picoCuries.
The dark red shows areas where most homes have radon levels above the suggested EPA limit. Note that the radon estimates for the ‘red’ counties is maybe 20 times the exposure levels in the ‘blue’ counties.
Most Colorado counties, including Archuleta County, are “green” — meaning that maybe a quarter of the homes exceed the EPA’s recommended limit.
Curiously enough, the human body is itself radioactive, due to various radioactive elements contained inside our bodies, including potassium, iodine and carbon. In some places in the U.S., a person may be exposed to more radiation from inside their own body than from residential radon.
But that gets us into the whole question of low-level radiation, and how dangerous it might — or might not — be. What exactly is the health effect of daily exposure to 4 picoCuries of radiation from radon gas?
Or 10 picoCuries, for that matter?
Here, the EPA has made a couple of scientific assumptions, which might have a real-world relevance similar to sitting in a sewer to prevent bubonic plague.
It’s pretty well acknowledged that, historically, persons exposed to nuclear bombs have elevated cancer rates. What we know with much less certainty is whether a person exposed daily to, say, 10 picoCuries of radon gas is likely to develop lung cancer. (10 picoCuries is the amount of radiation emitted by 0.000000000001 gram of radium.)
The science is complicated, but from what I can tell, the EPA looked at very high radiation exposures and counted the number of cancer cases, and then did a linear mathematical extrapolation to calculate of the number of cases that might occur from lower doses… making the assumption that the trend is linear. Their estimate? 21,000 cases of lung cancer per year, from radon exposure.
But maybe… it’s not linear? Maybe… it’s the opposite of linear?
We know from statistical studies that smokers are more likely to develop lung cancer than non-smokers. We know this because we’ve actually counted the cases of lung cancer in each group, adjusted by the number of cigarettes smoked. It’s pretty simple statistics.
Studying radon gas exposure is more challenging, because some people like to open their windows to let in fresh air — and some don’t. Some people spend a lot of time in their basement — where radon is most concentrated — and some spend time upstairs. Some people are home all day; other people spend a lot of time outdoors.
To make things even more difficult, a particular house might have very high radon exposure, while the house right next door has no radon at all.
Here’s that map again, showing, in red, the areas of the country with very high levels of radon gas in the soil… and areas of the country, shown in blue, with almost no radon gas in the soil.
And here is a map showing the incidence of lung cancer, as reported by the National Cancer Institute. The red color indicates a high incidence of lung cancer; the blue indicates a low incidence.
As we can see, the U.S. counties with low levels of lung cancer correlate pretty well with the areas, in the previous map, showing the highest levels of radon gas found in homes.
The correlation is exactly the reverse of what the EPA has been telling us.
If the EPA scientists were looking at these two maps, and thinking about what they were seeing, they might surmise that moderate levels of radon gas actually prevent lung cancer.
But the EPA is not looking at these maps. They’ve been working from a scientific theory about radiation, called the ‘Linear No Threshold’ theory, or LNT. For those interested in a further discussion of LNT, here’s a 52-page scientific paper on the topic from the University of Oslo, Norway.
Okay. Sounds crazy. Moderate levels of radon — the levels typically found in Colorado homes — actually lower the risk of lung cancer. Who could accept such an idea?
Maybe… our BOCC?