In researching the subject of Radon mitigation, I came across this article
http://www.forensic-applications.com/radon/radon.html, Titled "Radon - A brief discussion", by Caoimhín P. Connell (Forensic Industrial Hygienist)
Please read that whole article before posting any comments. It's a long read, but I'd like to ensure everyone who comments on this topic has in fact read and understands the article. No biases please! :)
The first paragraph states the following:
A large portion of the general population is under the misconception that the frequently published risks associated with radon are well accepted scientific facts. In reality, the vast majority of well designed studies do not support policy or positions that exposures to indoor radon pose a significant threat to health, and indeed, the majority of those studies indicate that, at concentrations typically seen in homes, as the level of radon increases, the risk of lung cancer goes down, not up.
After reading the science behind Caoimhín's well-written and thorough article, I have to say I agree with his words and message. So what does that mean to an energy auditor? What advice am I to give to a homeowner whose home is under constant depressurization causing backdrafting with their woodstove or failing to pass worst case combustion safety tests, all because of their radon fan in the (nearly-conditioned) crawlspace? I realize as a BPI graduate I am supposed to consider Radon. But what do I tell folks whose Radon mitigation system indicates levels far below 7 picocuries? Should they run that fan that consumes 526 kWh/year, costing them $70/year?
I welcome your input. Love this community!
Hello Mr. Millard:
As Rodney points out, the questions being raised are valid, and actually, it would appear that overall, I’m the one who agrees with the EPA, and you and Mr. Cullen are the ones who disagree with the EPA regarding radon.
The EPA says:
Exposure in the U.S. cohort is poorly known; cumulative WLM (CWLM) are calculated from measured radon levels for only 10.3 percent of the miners...and guesswork is used for about 53.6 percent of the miners.
I agree with them – they used guesswork – guesswork is not science; guesswork is just guesswork. Apparently you disagree with the EPA and don’t think they used guesswork and you think they used some kind of scientific evaluation process. If I had come on to this forum and based my opinions on my “guesswork” I would have (rightly) been excoriated, because guesswork is not supportable science.
The EPA says:
Although there is a growing body of data from epidemiological (case-control) studies showing a correlation between lung cancer and radon exposures in homes, these results do not conclusively demonstrate an excess risk in homes with elevated radon and are inadequate as a basis for quantitative risk estimation.
Well, since the EPA contradicts itself in this statement, it’s difficult to know their position. I agree with the EPA, there is a growing body of evidence that continue to show a correlation between lung cancer and radon in homes – that correlation is consistently a negative value, meaning that as radon levels go up, lung cancer rates go down. We see those studies starting from Dr. Cohen’s stuff in the 90’s and continuing with Thompson’s 2011 study published in the journal of the International Dose-Response Society (Dose-Response, 9:59–75, 2011).
There is very clearly a correlation and that correlation is negative which is why the EPA then says “these results do not conclusively demonstrate an excess risk in homes with elevated radon” I agree with the EPA, the studies do not conclusively demonstrate an excess risk in homes with elevated radon. I agree with the EPA!
The EPA says:
Thus, estimates of risk for indoor exposures must still be extrapolated using models derived from the miner data. There are a number of important differences between mine and indoor exposures that must‚ be considered in making this extrapolation.
Well – the EPA says they don’t like the science, because the science shows correlations (with negative values), and the EPA doesn’t like facts, so they’re going to use their “guesswork” instead, but the EPA says “There are a number of important differences between mine and indoor exposures that must‚ be considered in making this extrapolation. ” Well, I agree with that, and therefore, I wonder why the EPA didn’t do that? Do you know why the EPA chose “guesswork” instead of legitimate and growing body of data from epidemiological (case-control) studies showing a correlation between lung cancer and radon exposures in homes? I know why.
(By the way, I also completely agree with the US Department of Energy (who didn’t use make-believe “guesswork” and concluded:
Despite being widely accepted as a guideline in setting standards for protecting public health, the linearity hypothesis is not firmly established as an expression of scientific knowledge
The EPA says:
An ecological study has indicated that lung cancer rates are negatively correlated with average radon concentrations across U.S. counties (Cohen 1995), suggesting that the risks from very low levels of radon have been overestimated, or that such exposure levels might even protective against lung cancer.
I completely agree with the EPA, and it would seem that you disagree with the EPA.
The EPA says:
The only human data available for predicting the risks to the public are studies examining the health effects of exposure to radon and its progeny in underground miners. This information would be appropriate for predicting the risks to the public if everyone was a miner, everyone lived in mines, and a large fraction of the general population smoked cigarettes.
Well, wait minute, if “The only human data available for predicting the risks to the public are studies examining the health effects of exposure to radon and its progeny in underground miners.” Then what about the “…growing body of data from epidemiological (case-control) studies showing a correlation between lung cancer and radon exposures in homes, these results do not conclusively demonstrate an excess risk in homes with elevated radon …”? So, is there a growing body of data or not? And if, as the EPA says there is, then how could it be true that “The only human data available for predicting the risks to the public are studies examining the health effects of exposure to radon and its progeny in underground miners.”? Well I don’t know, but, I do know that I completely agree with the EPA that “This information would be appropriate for predicting the risks to the public if everyone was a miner, everyone lived in mines, and a large fraction of the general population smoked cigarettes.” I completely agree with the EPA on that account.
The EPA says:
Third, the exposure rates in homes are generally lower than the lowest levels for which we have clear evidence of excess risk in mines.
I agree with the EPA – and therefore, I have to ask: Then why did they use the guesswork, knowing that [t]his information would be appropriate for predicting the risks to the public if everyone was a miner, everyone lived in mines, and a large fraction of the general population smoked cigarettes” While knowing that everyone is not a miner, nobody lives in a mine, and a large fraction of the population doesn’t smoke cigarettes? I agree with the EPA that the use of the make-believe (guesswork) “data” was not appropriate.
The EPA says:
Although the miner data and radiobiological data are both suggestive of a constant risk per unit exposure as one extrapolates downward from the lowest miner exposures, this assumption has been questioned.
I agree – it has been questioned because scientists behind the growing body of data from epidemiological (case-control) studies showing a correlation between lung cancer and radon exposures in homes, that are not guesswork, but are actual data and these results do not conclusively demonstrate an excess risk in homes with elevated radon have questioned the sanity of using make believe “guesswork” – I think that is healthy questioning.
The EPA says:
The BEIR VI committee adopted the linear no-threshold assumption based on our current understanding of the mechanisms of radon-induced lung cancer, but recognized that this understanding is incomplete and that therefore the evidence for this assumption is not conclusive.
I completely agree with the EPA that it is an assumption based on “guesswork” and therefore, the assumption is not conclusive, which is why we see a growing body of data from epidemiological (case-control) studies showing a correlation between lung cancer and radon exposures in homes, that are not guesswork, but are actual data and these results do not conclusively demonstrate an excess risk in homes with elevated radon.
Actually, the BEIR didn’t adopt the NTLDR based on “current understanding,” as alluded to the fact that it was an inconclusive assumption, they chose the NTLDR because it was the model that best fit their make-believe “guesswork” data. If they used a better model, they would have had to adjust their make-believe guesses to better fit the facts.
The EPA says:
Unlike what was found with the more limited BEIR IV and ICRP analyses, the BEIR VI committee was able to conclude that the ERR per WLM increased with decreasing exposure rate or with increasing exposure duration (holding cumulative exposure constant).
I agree with this, Mr. Millard, and apparently you disagree with the EPA’s position, would you mind explaining why you think the EPA is wrong?
Finally, I also agree with the Health Physics Society who says:
Radiogenic health effects (primarily cancer) are observed in humans only at doses in excess of 10 rem delivered at high dose rates. Below this dose, estimation of adverse health effects is speculative. Risk estimates that are used to predict health effect in exposed individuals or populations are based on epidemiological studies of well-defined populations (e. g. the Japanese survivors of the atomic bombings in 1945 and medical patients) exposed to relatively high doses delivered at high dose rates. Epidemiological studies have not demonstrated adverse health effects in individuals exposed to small doses (less the 10 rem) delivered in a period of many years.
Apparently, Mr. Millard, you are more knowledgeable about radiological effects than these Health Physicist guys (shees… what would they know, right?)
So – on the whole, I agree with the EPA: There is a growing body of evidence that entirely fails to support the models used, the models used by the EPA would be appropriate for predicting the risks to the public if everyone was a miner, everyone lived in mines, and a large fraction of the general population smoked cigarettes, the results do not conclusively demonstrate an excess risk in homes with elevated radon, the exposure rates in homes are generally lower than the lowest levels for which we have clear evidence of excess risk in mines. Why don’t you agree with the EPA on these points?
Regarding the issue of vapor barriers increasing the moisture levels in homes, I will address that on Wednesday. Before I do that, I would like those following this thread to ponder the following question:
At what point was it ever established by Mr. Millard that the air in the crawlspace had ANY impact at all on the quality of the air in his occupied space?
I will address the myth behind that issue next week.
You have an interesting way with words, that's for sure.
I don't claim to have any more knowledge than anyone else on this issue. The EPA gives guidance and I follow it.
I can just see the conversation with the homeowner: "Well, the EPA says you should mitigate at over 4, but they admit to a faulty methodology based on inconclusive science, which may or may not have any bearing on the risk, but a bunch of scientists agreed that are health risks associated with radon, however there is an article online which says you really shouldn't do anything at all (except turn on your fan I guess) and no I haven't tracked down all the references in that article, so yeah, whatever you think."
There is a strange insistence on the part of Mr. Caoihmin to take on established building science practices, including this odd side conversation about vapor barriers, crawlspaces, etc. I think I'll just stick with Joe Lstiburek, thank you very much.
Thanks for giving a rational and coherent voice to my thoughts on this matter Cameron. Much obliged.
We are on the cusp of having lots of affordable tools for measuring various aspects of IAQ, so hopefully we can abandon the "best guess" approach for measured results soon.
I'd agree, if you found the work you did made your home more pleasant, it's a win. I asked the energy question because that's another measurable data point. If you reduced energy use, win also.
That said, I really like Caoihmin's approach to critical thinking. One of the greatest problems we have building credibility in Home Performance is success and performance are almost never measured, and because we don't measure accountability for results and consumer confidence is non-existent. The complete opposite of a virtuous cycle.
Don't know about other areas, here in Washington state we have fairly rigorous science by UW Medical School & in USGS that identify strata that emit radon that it is a health hazard for real thus work must be to the new standard for new construction in those areas, it's not a blanket code afaik, so, suspect most builders value their license enough to comply.
Low-level radiation sickness with so many chemicals we're exposed to is hard to detect doesn't mean it's not there that's where experimental work fills in the blanks, so, I disagree with opinions expressed here and have studied low-level radiation poisoning's effects on people including Hiroshima and Nagasaki residents more thoroughly after visiting those cities & meeting with survivors.
As regards vapor barriers also the locale will matter for the wet side of the Cascades it's a good idea for a crawl space in most cases, as a thermally aware designer I object to not using a crawl space as a thermal-mass battery to store heat-cold for the home.
Used 3" aluminum irrigation pipe makes cheap ducting to heat-cool the dirt being used & plugs into 3-1/4 x 10 ducting with standard fittings. So instead of just draping some plastic over the mess and plopping a fan somewhere put in a thermal stack, solar-thermal can then heat-cool the house most of the time for the fixed price of the system versus paying for those Joules by-the-watt from the grid, or in more battery-inverter capacity if onsite solar-wind.
Do your thing, installing a thermal-mass seals it for radon if one must do the work anyway, seems a best-buy on the sustainable dollar for new construction, adds little to the cost of compliance, and if anyone took accounting it's way cheaper per year to install solar-thermal on an amortized capital expense than buy watts, just not commonly done.
To know why to install a thermal-mass one probably took heat-transfer physics or studied it well.
The EPA gives guidance and I follow it.
Actually, this statement is indicative of many problems we see. Without getting too political, I will say that following government agencies blindly, knowing fully well any branch of government can be purchased (in this case, the Tobacco Industry lobbying the EPA), seems negligent and a disservice to our clients.
Shame on We the People, for looking for actual truth. For shame... ;)
The EPA site sends you to the state for details, they do list an international & two major USA standard methods of remediation, but for details you end back at your state's concerns, that gets broken down to counties or jurisdictions where it matters.
If you measure and there's no risk there's nothing to do and DIY meters are listed our state public health website, for real estate many brokers just demand doing it to help sell a new home so they don't really count for needs.
Low-level radiation poisoning is real from radon, do medical research on it, there is too much evidence it causes cancers in homes that are bad so most of this seems intellectual, as I stated before it's not necessary to have high concentrations to get a cancer, a builder won't ignore it with code demanding it for a lot with radon in the strata.
Again pointing to logic and if you have to spend the money to remediate, then install solar-thermal or be short-sighted on the resale value of the home.
My statement is a simplification. I've spent significant time learning about the health risks related to radon from a myriad of organizations. My point is simply that, short of any general widespread consensus from the scientific community, I think it is better to follow the precautionary principle which puts the burden of proof on the side saying radon doesn't cause cancer. Unless 20,000 deaths every year from non-smoking related lung cancer can be proven not to have resulted from radon then we should continue to take precautions.
A simple question comes to mind: "How much radiation from radon would you like to be exposed to? Or would like your kids to be exposed to?" The answer will vary depending on how much education you have on the subject, point of view, etc., but most people (including me) would say none!"
As far as the accusation that I'm avoiding critical thought on the matter, that's a red herring and doesn't validate any argument yet presented for ignoring radon.
Finally, the building science points that have been brought up are obviously related to the topic of discussion in terms of relative impact to the whole-house system. I've not yet seen a professionally installed radon in hundreds of home visits that has back-drafted an atmospherically drafted appliance. It's a non-issue if the right practices are followed.
"Unless 20,000 deaths every year from non-smoking related lung cancer can be proven not to have resulted from radon then we should continue to take precautions."
Hmmm, let's follow THAT line of thinking a bit. Based upon that logic, this would also be true:
I think the cause is people aren't lighting a dollar bill on fire and doing the hokey pokey. Since there is no evidence this is NOT a best-practice preventative measure, shouldn't we all implement this precaution until further notice?
And we should also remain indoor during daytime to prevent exposure to radiation.
Following a "better safe than sorry" line of reasoning great when there is evidence, but not in the absence. [Text removed due to non-compliance with Home Energy Pros Guidelines]
[Text removed due to non-compliance with Home Energy Pros Guidelines]
Again, more personal attacks. Having a bad day, are we?
This is a logic fallacy, "Following a "better safe than sorry" line of reasoning great when there is evidence, but not in the absence.".
Absence is not proof of non-existence, this assumes all evidence is always available for every circumstance, in this case it's obviously controversial thus back to the risk factor, again low-level radiation is very difficult to prove without GIS data on populations & geology combined.
The restrictions are NOT BLANKET, they are specific to conditions onsite only, that's a reasonable estimate of where to respond to risk.
Again, realtors will win this play on words, they'll just demand it and that's why I say look at the small increase to remediate what's not there, eh? ... the radon job is a sales gimmick, so if doing that make use of the capital spent by eliminating heating-cooling bills to a monthly payment for the system?
You're choice regardless, carry on.