• Bruce Schaepe
    It's been a couple of years since I brought this up on the old University of Iowa listserv, but I see absolutely no progress so I am bringing it up again. Specifically, the United States EPA and at least my state regulators here in Minnesota have been using one estimate without modification or update since 1999. That estimate is that "Radon causes 21,000 deaths in the United States every year".
    I am not a toxicologist, but I did do some online research in the past couple of days. It appears that the 1999 BEIR VI Report estimated annual deaths in the US in 1995 that were due to radon exposure at either 15,400 or 21,800 with a range of error between 3,000 and 33,000. In 2003 the "EPA Assessment of Risks from Radon in Homes" utilized the BEIR VI methodology to estimate 1995 deaths at 21,000 with a range of 9,000 to 50,000.
    Current EPA documents such as the "Citizen's Guide to Radon" and several others continue to quote the 21,000 annual death estimate and rightfully reference the 2003 report. EPA should be embarrassed to continue to quote an estimate that is nearly 25 years old. Oh yeah, I forgot who is running EPA (not sorry for the snarky comment).
    The continued use of the same estimate really undermines all the efforts and good work done both by AARST and all of the radon testers and mitigators nationwide who are trying to safeguard people in their homes. At the very least, continuing use of the same estimate does not consider:
    • The increase in US population from 266 million in 1995 to 329 million in 2019 (per US Census).
    • The houses that have been mitigated in the past 25 years. I hope that the number is not insignificant.
    • The smoking rate has been reduced since 1995 which means that there should be more people in the never-smoker category which has a lower lung cancer rate due to radon than for smokers exposed to radon.
    Let the rotten tomatoes begin to fly.
  • Kevin M Stewart
    No rotten tomatoes here. (Mine are still green.)

    I have also expressed discomfort in being relegated to the use of the estimate of radon-induced lung cancer deaths in 1995. Bruce, I think your summary is reasonably fair and your question is a good one to ask. However, I would not be so inclined to lay blame on EPA. Over the years when funding levels have continually decreased in real terms, and have long been under threat of being zeroed out, I recognize that EPA radon staff have had to work hard just to keep the radon program alive and functioning. While I'm sure they would also like to improve the estimates, to do a scientifically defensible job of doing so I'm afraid might require resources that they simply do no have.

    Bruce, you hit on the right factors, I think. I would also add the evolution of indoor environments over the decades in terms of what radon levels turn out to be under current air-exchange characteristics. As you know, there are indications that the old EPA indoor radon data may be underestimating current values.
    One other point: The EPA 2003 report discusses the risks associated with only residential radon exposure. While collectively smaller, risks associated with exposures in schools, workplaces, other indoor environments, and even in outdoor air, are not zero. I have attempted to make estimates of lung cancer deaths from radon along the lines that Bruce asks for, and taking into account all such environments, but I will be the first to emphasize that these have been "back of the envelope estimates by a non-expert amateur."

    People such as Dr. Bill Field may be able to add more about thinking that has been done since 2003 on the issue you raise. For example, see the relatively recent study at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4768325/ even though that study's conclusions about US lung cancer deaths from radon haven't yet, to my knowledge, been adopted as better replacement values in any widespread way.
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