SALT LAKE CITY — After 25 years as an environmental engineer and inspector, I learned that sometimes “common knowledge” and the facts can be very different. I learned that there is no source quite like the proverbial horse’s mouth. Often, my search for facts meant dodging people who insisted that I accept their opinion on a subject. This was frustrating to more than one superior in the workplace, eventually resulting in my choosing a career where I reported to no one (no one except my wife, that is).
The Utah State Legislature is currently considering legislation regarding radon abatement. Radon has been widely reported as being a menacing problem, and the list of agencies calling for radon reduction is long. Every one of these organizations is ultimately gathering their information from one source: The “EPA Assessment of Risk from Radon in Homes.”
This report represents the best that science can deliver, and was done by very bright individuals. There is no reason to discredit the report, but it's important to understand what it states, as opposed to what we're told it states. Perhaps half of the problem is this: Reading these types of documents is brain murder. These tasks are generally left for those with IQ’s of over 200 — and those who enjoy self-torture. These reports don’t read like a novel.
- Colorless, odorless gas, like oxygen and nitrogen.
- Originates naturally everywhere.
- Every breath that we all take includes some radon.
- All building floors located at or above the ground level have concentrations of radon.
- Normal levels are 1 to 2 pCi/l.
- Recommended threshold is 4.0 pCi/l
Radon is a colorless, odorless gas — a gas like oxygen and nitrogen. It originates naturally everywhere, and there is no place on earth you can go to get away from it. Every breath that we all take includes some radon. Background (normal) levels are 1 to 2 pCi/l -it’s impossible to get your home below that level. In homes, generally all floors located at or above the ground level will have background radon concentrations.
Prior to that most recent publication on Radon, EPA set a recommended threshold for safety at 4.0 pCi/l. Based on computer assessments, EPA found that if a non-smoker was in the affected area for 19 hours per day, for 72 years, then their risk of dying from radon would be about the same as their risk of drowning. Clearly, few if any of us will ever live in any affected area (i.e., a basement) for 19 hours per day, for 72 years. In any case, these are the conservative assumptions the EPA used to arrive at that risk conclusion.
Garbage in, gospel out
As an environmental engineer in the radiation engineering consulting industry during the mid-1990’s, I was directed to use similar conservative assumptions to complete risk assessment reports. These final reports were forwarded to the EPA, then to the public. Some of us remember a term invented by computer nerds like myself back in the 1980’s: “garbage in, garbage out.” This means that when inputs to the computer were unreliable, the output should be considered to be unreliable as well. As scientists, we often joked that the term should be “garbage in, gospel out.” It’s easy to arrive at a more dramatic bottom line via computer when you feed in more “conservative” assumptions.
Being conservative is what environmental professionals are expected to do. The reasoning is that it’s better to be conservative — even perhaps extremely conservative — than to have your work called into question for perhaps understating the risk.
Your basement: dungeon of doom and disaster
Radon is heavier than air. This means that it flows into your home naturally from the soil, then pools in the lowest level of your home. For many of us, that means that the basement will have the highest concentrations of radon. EPA recommends that you test a few feet from the floor in the basement or lowest living space within the house. This seems reasonable, until you realize that the EPA also assumes that you’re living in that space 24/7 for your entire life. The latest EPA computer model doesn’t allow you to have a job, to go upstairs or go to the grocery store. It assumes that you will never shovel the sidewalks or eat dinner on the main floor of your home. EPA’s latest computer model also assumes that you never eat out and never move to a different home; you’re in that "affected area" for your entire life. This is another “conservative” assumption used in the latest round of radon risk assessment.
What the report really says
All of the above notwithstanding, EPA’s report could be taken at face value. The report calculates annual lung cancer deaths from radon to be about 21,000, with an uncertainty range of 8,000 to 45,000. These values are subject to a number of uncertainties (most of which are identified in the report) and certain risk-reducing factors that are not considered. These are very briefly described below:
Uncertainty 1: The Monte Carlo method
When analysis gets difficult due to high numbers of variables, analysts often choose the Monte Carlo method. Without getting into a detailed description, this method is used when there is significant uncertainty. The Monte Carlo method leaves a great deal of opportunity for a computer modeler to be very conservative with little fear of being questioned; the inputs are buried in a mountain of data.
Uncertainty 2: Cohen
BL Cohen is a respected scientist, cited in the EPA report. He has found that lower levels of radon such as those found in homes are not only not bad for you, but may actually prevent or reduce lung cancers. The EPA’s conclusions don’t account for his findings in any way.
Uncertainty 3: Miners vs. moms
How much time have you spent in a mine? Get ready for some big words, right out of the EPA handbook: The risk assessments used a statistical analysis of data on 11 cohorts of occupationally exposed underground miners.
Miners, of course, are subject to more than just radon. Dust, arsenic, silica, diesel fumes, carbon monoxide and yesterday’s rotting lunch will affect a miner’s lungs. These are not accounted for as risk factors for a miner’s lung cancer risk — only radon.
Different as a mine may be from a family room, it is this mining data that the EPA has used to infer risk to a residential home and family. Even the miner’s health data isn’t conclusive: Lung cancer rates varied dramatically from one “cohort” to another.
Uncertainty 4: Second place, two-man race
Have you heard the ads about radon? Usually the ad will mention that the EPA considers radon to be the second greatest cause of lung cancer. This is frightening, but consider this: What is the third leading cause of lung cancer? One respectable website tries to answer that question. It cites smoking, but that’s also the leading cause. The question may be this: If you come in second in a two-person race, how well did you do?
If you have a stomach for scientific and engineering report-speak, here’s some nice bedtime reading. EPA’s report on radon has a 15-page section outlining the uncertainties. The many uncertainties that go into the report may not yield a reasonable conclusion that the output results are gospel.
Real risk reduction A: 24/7/lifetime
To rephrase what has been described above, the EPA reports that its most current model “Assumes constant lifetime exposure in homes at these levels.” In other words, you never leave the basement. If in reality you spend an average of two hours per day in your radon-affected basement, then the EPA model for you conservatively assumed a value 12 times too high. Your actual risk will be much less than the EPA would have calculated for you.
Real risk reduction B: contribute vs. cause
As described above, EPA’s report estimates that radon contributes to 21,000 deaths per year, with a wide uncertainty range. In short, the word "contribute" means that authorities will count a lung cancer death as a radon death if it contributes. This means that if a person dies at 90 years old with lung cancer, and he has radon in his basement, that’s a radon death. It makes no difference that most of the very aged are incapable of navigating themselves to and from the basement; it’s a radon death because radon may have contributed.
Then things get more interesting. Assume for a moment that you are driving down the road, texting, drunk and driving at 100 mph. You may also have the radio turned up. Then you get in an accident and die. While it is true that the radio contributed to your accident, few would list it as the cause of the death. It is important to differentiate between the words "contribute" and "cause" when dealing with radon. Few if any will presently make that distinction.
Real risk reduction C: Short-term tests
Want to find out what your radon levels are? Then you should test. Be aware that short-term tests are “conservative” (i.e., may overstate the value) and will change based on the season. [EPA recommends that you do a long-term test](http://www.epa.gov/radon/pubs/citguide.html#long term testing) before spending your hard-earned money on a radon mitigation system.
A successful marketer once explained that to motivate people, a business owner must use one of two tools: fear or sex. Clearly, businesses from Victoria’s Secret to Carl’s Jr. have used the latter successfully. If you’re in the radon business, you have to go with the former.
Money may be at issue. When the message is that something is less hazardous, less dramatic and less frightening, there is less interest. Fewer mitigations systems are installed, fewer magazines are sold, fewer inspectors will inspect, and fewer politicians will stand up and pronounce themselves to be the solution.
The $10/$10,000 rule
A common theme in home-related issues is that there is a $10 fix and a $10,000 fix to most issues. The $10 fix is always better, but requires more knowledge. In the case of radon, an example would look like this: test your basement for radon. Look at the results. Compare them to the EPA’s target (4.0 pCi/l), consider if anyone is living in the affected area, and decide if you need to go with a full mitigation system or a $2 tube of caulk.
Have questions? Visit www.crossroadsengineers.com or homemedic.tv to download the Household Hazards Handbook. It's free. Garth Haslem is a home inspector, author, professional engineer & regular KSL contributor. Follow "The Home Medic" on Facebook.