Radon Inspections


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Common Questions

The testing instructions are not very clear to me. Can you help?

Sure can. The first thing to do is select an area that is going to be occupied for 4 hours or more per day. This area needs to be on the lowest livable level of your home. Record all information, start time, date, location, device number, and all your pertinent information on the form supplied with the test kit. Do it now as time has a way of making you forget. The testing should catch a good part of the heating season, the optimal time of year to test is from October to April for at least 3 months. If you start a test in the summer months, that is fine, just ensure it goes into the heating season as well.

Now the specific placement is to be 50 cm from an exterior wall or 40 cm from an interior wall, in the range from 0.8 m to 2 m off the floor, at least 50 cm from the ceiling, and try and keep a 20 cm from other objects. Make sure this location is not near a heat vent or fans.

Do not place the test in a closet, cupboard, in the kitchen, in the laundry room, in a crawlspace, or in a bathroom.

What is Radon?

The natural radioactive element Uranium is present everywhere in rocks and soil. It is the radioactive decay of Uranium that produces Radium, which in turn decays to Radon, a radioactive colourless, tasteless and odourless inert gas. As it is a gas, it can move easily through bedrock and soil and escape into the outdoor air or seep into a home or building. Radon may also be present in water. Radon moves from the ground into the outdoor air where it then rapidly dilutes to low concentrations and is not a significant health concern. It becomes a health concern when it can build up to significant levels indoors due to the lack of fresh air dilution. The only way to know if Radon levels are elevated or not within your home is to test for it.

How did they find out about Radon?

In 1984, Stanley J. Watras was a construction engineer at the Limerick nuclear power plant in Pottstown, Pennsylvania. A monitor was installed at the plant to check workers to make sure they did not accidentally accumulate an unsafe dose of radiation at work.

One day, on his way to work, Mr. Watras entered the plant and set off the radiation monitor alarms that help protect workers by detecting exposure to radiation. Safety personnel checked him out, but could not find the source of the radiation. Interestingly, because the plant was under construction at the time, there was no nuclear fuel at the plant, so there was no way for Mr. Watras to have been exposed to any radiation at work.

Eventually, they discovered that Mr. Watras was not picking up the radiation at work, but rather was bringing it to work from home! A team of specialists was sent to the Mr. Watras’ home to investigate. There, they measured radiation levels about 700 times higher than the maximum level considered safe for human exposure (the home tested at 2,700 pCi/L and a safe level is at or below 4 pCi/L). The source of this enormous amount of radiation turned out to be radon, a naturally-occurring gas that made its way into the Watras home from underground. It had nothing to do with Mr. Watras’ job. The entire family was living in an environment roughly equivalent to smoking a couple of hundred packs of cigarettes per day. They moved out of the house immediately, while the problem was being fixed.

After Mr. Watras and his family evacuated their house, the United States Environmental Protection Agency (EPA) and Pennsylvania officials turned it into a laboratory for long-term measurement of radon and radon decay products and evaluation of radon mitigation techniques. After many months, they reduced the radon concentration to an acceptable level, and the family was able to return. After installing a radon-reduction system, radon levels in the home tested below 4 pCi/L.

Radon is a Class A carcinogen, which means it is known to cause cancer in humans. Most people do not know that radon is the second leading cause of lung cancer in the Canada, resulting in approximately 3,200 lung cancer deaths each year. Only smoking causes more lung cancers.

What are the health hazards associated with Radon?

The only known health risk associated from exposure to Radon is an increased risk of developing lung cancer. The risk increases considerably from higher concentrations of Radon, length of time to exposure, and smoking habits.

Health Canada estimates a non-smoker that is exposed to elevated levels of Radon over a lifetime has a 1 in 20 chance of contracting lung cancer. If a smoker was exposed to the same levels as the non-smoker over a lifetime, the risk increases to a 1 in 3 chance of contracting lung cancer.

Exposure to Radon does not cause other diseases or respiratory conditions nor will it produce symptoms such as coughing or headaches.

The estimated risk of  lung cancer from Radon exposure was originally based on exposures to high concentrations of Radon associated in Uranium mines. Recent residential studies have now confirmed that exposure to lower levels of Radon usually found in homes also carries a risk of lung cancer.

Is there any proof that Radon causes lung cancer?

As with most illnesses, cause and effect can not be 100 percent proved.

If you have high blood pressure and suffer a stroke, studies indicate that your high blood pressure is the most likely cause.

Similarly, epidemiological studies have presented compelling evidence that Radon is the number one cause of lung cancer in nonsmokers and that smokers who are exposed to high Radon levels are 10 times more likely to get lung cancer.

How does Radon get into my home?

The air pressure inside a building is usually lower than in the soil surrounding the foundation. This draws in gases, including Radon, through openings in the foundation where it is in contact with the ground. This includes construction joints, gaps around service pipes and support posts, floor drains and sumps, cracks in foundation walls and in floor slabs, and openings in concrete block walls. Radon can also enter into your home from your drinking water. However this source is usually associated with deeper wells. Another potential source is from building materials but, there are very few cases in which this ended up in contributing excessive amounts of Radon gas into the interior of the building.

What happens after the Radon levels are reduced?

The Radon mitigator will retest your home to make sure the Radon level is reduced adequately.

To keep the Radon level down, the Radon fan must run continuously, so don’t turn it off or unplug it.

Check the “system performance indicator” such as a “u-tube monitor” from time to time to see if your system is operating properly, and re-test your home at a recommended rate of once every 5 years to make sure the Radon level remains low.

It is normal to have minor fluctuations in the Radon level.

How do I test for Radon?

You can either test your home yourself or hire a certified Radon testing professional.

If you choose a do-it-yourself home Radon test, you have a couple of choices. These choices are between a short-term or long-term test device. In either case, the best time of year to test is during the heating season (October – April). This is generally the period where our homes and buildings are more tightly sealed up and the radon levels would likely be at their highest.

Both are easy to use and come with step-by-step instructions. Keep in mind, however, that Radon levels are not consistent and therefore a short-term test may not necessarily represent your “annual average exposure levels” which is why Health Canada recommends “long-term test devices” to test your annual average Radon exposure levels.

What is a high Radon Level?

There really is no safe level of Radon exposure. However, with that being said, there are recommended guidelines for exposure limits set forth from Government and Health agencies. Health Canada recommends the following:


Radon gas is measured in Canada as Becquerels per cubic meter (Bq/m³) or in the US as picoCuries per liter (pCi/L). The current airborne radon level at which Health Canada recommends action is 200 Bq/m³ or 5.4 pCi/L. The US EPA guidelines are set at 4 pCi/L or 148 Bq/m³ the World Health Organization (WHO) guideline is set at 100 Bq/m³ or 2.7 pCi/L. These are all recommended guidelines and, the best advise is to obtain the lowest level of airborne radon you can within your financial limit.

Radon concentrations  in water can also be a concern and contribute to airborne Radon levels. High Radon in water levels are usually associated with deep water wells. Hot water “vapourizes” into the air by converting into steam and thus becomes an inhalation hazard of radon into the lungs. As a general rule, a measurement of 10,000 Bq/m³ of Radon in water will contribute roughly 1.0 Bq/m³ throughout the household air. This may also vary depending on the amount of water used, the air exchange rate of the building, and how much hot water / steam is created or used.



I don’t live in an area with any known high Radon levels, should I still complete a Radon test?

Even homes in areas considered at low risk for radon could have high radon levels. Although there have been no “absolutely safe levels of radon” determined; by following Health Canada’s guideline of 200 Bq/m³ or 5.4 pCi/L, the EPA recommendation of 148 Bq/m³ or 4 pCi/L or the World Health Organization’s recommended level of 100 Bq/m³ or 2.7 pCi/L, you will be helping to protect yourself and your family. The only way to know whether or not you need to fix your home is to complete a test for radon. Health Canada recommends long term testing methods.

I have a new home with no cracks or other openings, so why should I test for Radon?

As a gas, Radon can seep through tiny cracks that you might not even see. It can get into finished or unfinished basements, and into new homes as well as old. You won’t know if it’s in your home unless you do a Radon test.
The builder said “my new home is radon resistant, so I can’t have Radon, right?”
Even if you have purchased a home with Radon Resistant New Construction (RRNC), unless you, the builder or a home inspector tested your new home for Radon, there is no way to know that the RRNC system installed is working as it should to reduce the indoor Radon levels. Although the name Radon Resistant New Construction implies that the home resists radon, very few contractors know how to install an effective system unless they have been specifically trained in Radon Mitigation. Bottom line is you should complete a Radon test regardless if your home is new or old and continue to re-test at a rate of once every 5 years thereafter.

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