What is a dangerous level of radon?

Answer 1

That is a good question. What we do know is that, contrary to popular belief, there is no known additional risk of cancer associated with radon levels as normally seen in houses. In fact, there is no science to support the common practice of radon measurement and radon mitigation in homes. The common practice is a "policy practice" not supported by science. Most (in fact virtually all) of the risk assessments done to date, that support the radon industry, rely on, or reference selected passages from the US Environmental Protection Agency (EPA) reports. However, if we actually go to those exhaustive studies we see that in the "latest" EPA risk estimates, on Page 13, the EPA tells the public: 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. Thus, estimates of risk for indoor exposures must still be extrapolated using models derived from the miner data. EPA Assessment of Risks from Radon in Homes (United States Environmental Protection Agency; Air and Radiation (6608J) EPA 402-R-03-003, June 2003) Let's look at this statement in detail. What the EPA means by this is that although there is a growing body of data from epidemiological (case-control) studies showing a correlation between lung cancer and radon exposures in homes, that "correlation" to which they are referring is actually a NEGATIVE correlation. In other words, the correlation is inversely related to the radon concentration - This means that the growing body of data from epidemiological (case-control) studies are showing that the lung cancer rate DECREASES with increasing radon concentrations seen in residential settings. That is why the EPA "clarifies" their statement with "…, these results do not conclusively demonstrate an excess risk in homes with elevated radon…" In making this statement, the EPA is correct, since in fact they show just the opposite. The current wording allows the uninformed reader to lead themselves into thinking the opposite without the EPA actually having said it, unless they read the entire risk analysis study (which virtually no one reads). Next, the EPA states: Thus, estimates of risk for indoor exposures must still be extrapolated using models derived from the miner data. In other words, the EPA is saying that because the growing body of data from epidemiological (case-control) studies showing a negative correlation between lung cancer and radon exposures in homes, these results do not conclusively demonstrate or support the "policy" statements presented by the EPA and therefore, the studies are inadequate as a basis for quantitative risk estimation. But in fact, they are not. The objective truth is that the studies are showing exactly what health physicists and epidemiologists have known for years, but these findings are not in line with what the EPA has issued as a policy statement. So the EPA is forced to use studies of underground miners, extraplated to home occupants, since those are the only studies which would support the EPA policy, that is why the EPA says: Thus, estimates of risk for indoor exposures must still be extrapolated using models derived from the miner data.But are those studies even valid? Let's see what the EPA says about their own miner data on page 13 of the same document: There are a number of important differences between mine and indoor exposures that must' be considered in making this extrapolation. Indeed there are! The U.S. Department of Energy ("Radon- Radon Research Program, FY 1989, DOE/ER-448P., March 1990) agrees and stated: 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. However, we don't all live in mines, we aren't miners, and we (mostly) don't smoke - so why are we using this data? Furthermore, The National Research Council, ("Health Risks of Radon and Other Internally Deposited Alpha Emitters, BEIR IV", National Academy Press, Washington, DC., 1988) stated that the miner data is comprised mainly of "guesswork." Here is what the NRS said: 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. That is over half of the estimated exposures were guessed! Imagine that - GUESSWORK! Why is the EPA choosing to ignore valid epidemiological studies in favor of guesswork? And even on Page 2 of the new US EPA risk estimates, the EPA questions its own use of the guesswork and states: Third, the exposure rates in homes are generally lower than the lowest levels for which we have clear evidence of excess risk in mines. The EPA goes on to say: 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. It has in fact been questioned and indeed, it has been demonstrated to be completely wrong. (Cohen, BL. Test of the linear no-threshold theory of radiation carcinogenesis for inhaled radon decay products. Health Phys. 68, 157-174, 1995.) The EPA acknowledge Cohen's work in the new risk estimates and stated: 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. But qualified the observations thus: Numerous critics, including the BEIR VI committee, have discounted the (Cohen) ecological study results because of methodological limitations, and the biologically based models remain highly speculative. Imagine that - the EPA criticizes Cohen's studies as "speculative" even though it's own studies are based on guesswork. However, unlike the EPA studies, the Cohen studies did not involve "guesswork" which clearly "highly speculative." The EPA and the BEIR VI committee adopted what is known as the linear no-threshold assumption for radon-induced lung cancer, but recognized that this understanding is incomplete and that therefore the evidence for this assumption is not conclusive (or indeed, not even valid). In the 2003 risk estimates the EPA clearly stated that: 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. But Cohen in 1995 (referenced above) and many others since (such as Brüske-Hohlfeld, I; Rosario, AS; Wölke, G; et al. Health Physics March 2006, Volume 90, Number 3) have shown that the LNTDR curve is not valid, and the EPA itself says "that this understanding is incomplete" and the EPA also says "therefore the evidence for this assumption is not conclusive." So it begs the question: Why did the EPA, knowing that the model was not supportable by science, and did not agree with observed fact, use the model anyway? Well, a possible answer lies with financial gain. According to the SNM Committee On Radiobiological Effects Of Ionizing Radiation, the societal cost of testing and mitigation at the EPA recommended level was estimated at 44.5 billion dollars (1991), and that cost would rise to 101.2 billion dollars if the action level was lowered to 2 pCi/liter. Even at the NCRP action level, 8 pCi/liter, the cost is estimated at approximately 15 billion dollars. In other words radon testing and mitigation is good for the economy, even if the science doesn't support the industry. As it turns out, the EPA doesn't actually have ANY data that confidently demonstrates a positive correlation, or causation regarding radon in homes and lung cancer. But the EPA dismisses this problem and actually said that radon measurements in homes is not important for risk estimates in homes, but it is more important to guess at what miners were exposed to and then apply those extrapolated values to home owners. It is not likely that even a school child at a science fair would get away with such anti-scientific posiitons. Although there are dozens of studies that that measured radon in homes and failed to find an increased risk, or indeed a positive correlation, the EPA arbitrarily decided to ignore those studies since they do not agree with the "policy" decisions. On page 7 of the 2003 risk estimates the EPA states: The most important information concerning the health risks from radon comes from epidemiological studies of underground miners. But reasonable people want to ask: Why? Why not use the radon concentrations in homes to calculate the risk of radon in homes? Especially sinse the EPA it self notes the huge differences between those kinds of environments and on Page 24 of the 2003 risk estimates the EPA admits: However, exposure conditions in homes differ from those in mines, with respect to both the physical properties of the inhaled radon decay products and the breathing patterns in the two environments So why not use the data from homes? Simple - Because even according to the EPA: 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). This complex sounding paragraph is why - What this paragrpah means is that as the estimated concentration of radon goes up in an home, the risk of lung cancer goes down. So, we know a lot about radon exposures in mines, and we know that those exposures are extremely high, and we know they can be very dangerous, we also know a lot about radon in homes and we know that studies have shown that radon gas, as seen in homes has NEVER been demonstrated to increase the risk of lung cancer. As it is, the dose-response curves, and the actual science behind the issue do not support the policies of the EPA or any other government agency which used the EPA studies as the basis for their policies.

Answer 2

Maximun "safe" level for radon is 4 pCi/L (4 picoCuries per liter of air). *Please visit the discussion page and read another opinon. 4 pCi/L is not a "safe" level of Radon. There is no safe level of Radon, the risk is linear. Radon is a colorless, odorless gas that arises naturally within the ground from the decay of radioactive elements. It is the leading cause of lung cancer among non-smokers. The "action level" for home exposure is 4 picocuries of radion per liter of air (4 pCi/L). According to the US EPA, the average radon level in American homes is 1.25 pCi/L, and 6 million homes have levels of 4 pCi/L and above. Radon levels are not regulated; that is, there is no requirement for mitigation after a certain level is reached. State and local health departments commonly have programs, however, to reduce radon deaths by increasing awareness through outreach and education, promoting testing for radon, and using radon-resistant techniques in new construction. Contact your state or local health department to see if free testing is available. For more information, including maps of radon zones, go the the US EPA web site: http://www.epa.gov/radon/index.html.

Answer 3

In general, a level of radon gas equal to 4 picocuries per liter (pCi/L) is considered a "limit" as regards set standards. But remediation is recommended for anthing close to that, and is a "must" for anything above it. Be smart about this one. Radon is an underrated cause of cancer. Educate yourself and ward off trouble. There is help on the web, here at WikiAnswers, and from local agencies. Don't be afraid of radon. You're not afraid to drive a car. You know the risks and you manage them because driving has a low risk-to-benefit ratio; low risk and lots of benefits. Take on radon like this. Learn a few things and get out in front of any hazards you may be exposed to. Links can be found below to get you started on the physics. Everything from there is downhill.

Answer 4

In most countries a radon level above 4 pCi/L is considered high and requires a mitigation system to be installed in the building.