By Christine G. Crocker
Executive Director, Maine Indoor Air Quality Council

IN MAINE, HIGH LEVELS OF RADON GAS OCCUR naturally in our soil and water, a result of the breakdown of uranium in the granite upon which Maine sits. Radon is a colorless and odorless radioactive gas that gets trapped in buildings and causes lung cancer: it’s the #1 cause of lung cancer in nonsmokers and the #2 cause of lung cancer nationwide. The Maine Centers for Disease Control and Prevention (CDC) estimates that 33% of Maine homes likely have radon levels above the U.S. Environmental Protection Agency’s (EPA’s) recommended action level. And in Cumberland County, that estimate rises to 66%. Our lung cancer rates are proof of the risk: Maine has the third-worst rates of radon-induced lung cancer in the nation.

While radon-induced lung cancer may be scary, there is a lot of good news about radon risk: Lab tests are reliable, lowcost and easy to do; we have well-established action levels that clearly identify risk; and the costs to fix radon problems are often significantly less than other common home repairs, such as roof, electrical or plumbing repairs, or heating/cooling system changeouts. For a typical single-family home, it costs approximately $1,500 to install a radon-in-air mitigation system.

All buildings in Maine should be tested for radoN

You can’t tell by looking at your home whether or not it has high radon. Nor can you tell by what type of foundation it has, how old the house is, how many stories it has or by your neighbor’s test result. The only way to know whether or not your home has high radon is to test it. And now—during colder weather months—is the best time to test your home for radon, because your doors and windows are likely closed and your heat is on.

Testing in “closed conditions” gives you the best assessment of the potential risk to you and your family. If your home has a private well, you will need to test the water, too, since radon can be released from the water into the air inside your home.

Testing your home for radon is easy and can be done by you or a registered professional. There are three ways to test:

• Purchase test kits for air and water testing from a registered lab or at a hardware store or retail lumber outlet. These types of tests require laboratory analysis.

• Hire a registered tester. If anyone other than you is going to do the test, they must be registered by the Maine State Radon Section. (Note: If your home is for sale or you are looking to purchase a home, state law requires that any radon tests be done by a registered radon professional.)

• Use a device that continuously monitors the radon in the air. Indoor air quality (IAQ) monitors are available to continuously measure the level of radon and/or other pollutants in your indoor air and deliver that information on the device or a digital app.

Here is a quick guide for deciding which type of radon-in-air test to choose.

At what level should you fix your home’s indoor air quality?

You should fix your home if your test result shows your radon-in- air level is at or above 4 picocuries per liter (pCi/L) or if your radon-in-water level is at or above 10,000 pCi/L. Both EPA and the Maine CDC further recommend you consider fixing your home if your radon-in-air levels are between 2 and 4 pCi/L or your radon-in-water levels are between 4,000 and 10,000 pCi/L.

If your home tests high for radon-in-air or water, contact a radon professional registered with the State of Maine to install a system in your home to prevent radon exposure to you and your family. In most cases, available methods make it possible to get radon-in-air levels to 2 or below and radon-in-water levels to 4,000 or below. Talk with your radon professional about available options, costs and efficacy. Homeowners can also call the Maine Radon Section to discuss options: 1-800-232-0842.

Building radon out of your new home is now required in Maine

If you are planning to build a new home, installing a radon preventive system during construction is now required for all new home construction in Maine, even if your municipality doesn’t enforce the code. Installing radon preventive features at the point of new construction is:

• Cheaper: All the key features of the radon system can be installed in your new home for $500-$1,000, compared to $1,500 or more for a retrofit system.

• More effective: Installing radon preventive features during construction will make that system more effective at reducing radon-in-air levels to 2 or below.

• More energy-efficient: Radon preventive features installed during construction have straighter pathways, allowing for the potential that natural forces alone (without an electric fan) will keep radon levels at 2 or below.

• Verified: Your builder must test the home for radon before providing it to you and your family to live in.

Further guidance on how to build radon out of your new home is available through your local Codes official or the State Radon Section.

Don’t neglect radon when doing renovations or energy upgrades

Because radon is a gas, any renovation that changes how air flows around and through your home can impact your radon levels. Always test your air both before and after your renovation to make sure your home has acceptable levels of radon. If your pre-project radon test results are above action levels, work with your contractor to add the radon system into your project, possibly saving time and materials.

Are you a tenant in Maine?

Maine law requires that all landlords must test their rental properties for radon-in-air and disclose the test results to you before you sign the lease

Resources

• Maine State Radon Page – has tip sheets, regulations governing radon in Maine, and useful contacts and resources 

• Maine Radiation Control Program Page – Find registered Maine laboratories, testers, and mitigators.

• Abridged version of the Maine radon construction standard

• Reasons to consider an air quality monitor – Green & Healthy Maine HOMES article

These tips are provided by the Maine Indoor Air Quality Council, a nonprofit organization dedicated to the creation of healthy, productive and environmentally sustainable indoor environments. For more information about indoor air quality in your home, school or workplace, contact the Council at maineindoorair.org or 207-626-8115.

What’s my health risk?

Radon levels in Maine are measured in picocuries per liter (pCi/L), which are a measure of the rate of radioactive decay of radon. The action levels recommended by the Maine CDC and the U.S. EPA are hard to understand, because we don’t know what they really mean (just like it’s hard for us to interpret temperature in Celsius or speed in kilometers per hour). The following may help you understand the risks to your health from exposure to radon:

• 4.0 pCi/L (the minimum EPA action level) is the equivalent of smoking 8 cigarettes a day.

• 4.0 pCi/L is the equivalent of 200 chest x-rays per year.

• If you smoke and have elevated radon levels, your risk for lung cancer is especially high.

• Children may have greater radon exposure than adults because their lungs are smaller and they have faster breathing rates.

• The average radon-in-air level nationally is 1.3 pCi/L, while in Maine, our radon-in-air average is 5.9 pCi/L. (exceeding the EPA action level of 4.0 pCi/L).

• Nationally, 1 in every 15 homes has elevated radon levels. In Maine, it is 1 in every 3. In Cumberland County alone, it is 2 in every 3.

• Homes in the Sebago Lakes region have particularly high levels of radon, often upwards of 50 pCi/L in air and similarly high levels of radon in water.

• It is estimated that 310 Mainers contract radon-induced lung cancer yearly and 165 Mainers die from radon-induced lung cancer each year.

• Radon-induced lung cancer costs Mainers $62 million in medical costs (hospital, medicine and doctors) and $65 million in economic costs (lost wages and lost productivity).

This article appeared in the Winter 2024-25 edition of Green & Healthy Maine HOMES. Subscribe today!

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