By Connie Choy
November is Radon Action Month across Canada, to raise awareness about this potentially dangerous substance that can cause lung cancer. Radon is a naturally occurring invisible radioactive gas that comes from the breakdown of uranium in rocks and soil. Radon gas is present everywhere in rocks, soil and air but at outdoor levels, it is diluted and does not pose a risk to humans. In areas where the soil or rocks have high uranium levels, high radon levels can be found.
Radon can get into any building, such as a home, office or school, through openings in the foundation floors, walls or pipes and drains. Inside a building, radon gas is not diluted; it can accumulate and build up to high levels which can cause harmful health effects.
Exposure to high radon levels over time can lead to lung cancer developing as radon gas is inhaled and damages lung tissue. Radon is the leading cause of lung cancer in non-smokers and the second leading cause of lung cancer overall. Radon has been linked to 16 per cent of lung cancer cases in Canada. For people who smoke and are exposed to high radon levels, they have an even greater risk of getting lung cancer from the combined effects of smoking and radon exposure.
Every building will have some level of radon since buildings sit on top of soil and rocks. The important thing is to find out how much radon is found inside the building. The amount of radon that can get indoors depends on a number of factors such as the amount of radon in the surrounding soil and rocks, the pressure difference inside the building and outside in the ground which can cause more soil gas and radon to be drawn inside, the ventilation system and the amount of openings in the building foundation or walls where the radon can get inside.
When it comes to public buildings such as workplaces, schools and daycares, it is important to get the building tested properly. Health Canada recommends long-term radon testing, which involves having a radon detector set up for a minimum of three months preferably during the colder months of the year when the building is more airtight. A three-month measurement will give a more accurate representation of the annual average radon level inside the building.
For testing in public buildings, it is recommended that all rooms, occupied by someone for four hours or more per day, with floors or walls that are in direct contact with the ground or a crawl space should be tested. If there are no occupied rooms on the levels in direct contact with the soil, then all occupied rooms on the first occupied level should be tested.
Once the testing period is over, the radon detectors will be sent to a lab for analysis and the lab will send the results directly back within a few weeks. If the radon levels comes back above the Canadian guideline level of 200 becquerels per cubic metre (Bq/m3), action should be taken to reduce the radon concentration as much as possible. It is important to know that high radon levels can be fixed. The higher the level, the sooner action should be taken to lower it as much as possible.
A Canadian National Radon Proficiency Program (C-NRPP) certified radon professional can help find the best mitigation solution for the building. For more information on radon testing in public buildings, see Health Canada’s Guide for Radon Measurement in Public Buildings.
In late 2007, Health Canada initiated a countrywide testing program to measure the radon levels in federal buildings. The objective of this was to identify federal workplaces with radon levels above the guideline of 200 Bq/m3 and to encourage federal employers and building managers to address remediation, should it be necessary to ensure the health and safety of the building occupants. In the last five years, the National Radon Program has tested over 19,000 federal buildings. Results from this testing program indicate that approximately four per cent of these buildings had rooms that tested above the guideline. A survey to track the mitigation status on these buildings was initiated in 2014 and Health Canada is continuing to follow up with building managers to encourage remediation action for the buildings that tested above the guideline.
There has been lots of attention recently on encouraging all Canadians to find out about radon and get their homes tested. But it is equally as important for employers to protect their workers from high radon levels. In Canada, exposure to radon in the workplace is set from guidelines such as the Canadian Guidelines for Management of Naturally Occurring Radioactive Materials (NORM)
and the Canada Labour Code. Based on these guidelines, steps to reduce workers’ exposure to high radon levels should be taken. Although there is no legal requirement for employers to test their workplaces for radon, the only way to know if they are meeting the guidelines and ensuring their employees’ health and safety is to test.
Connie Choy is the air quality/smoke-free homes and asthma co-ordinator at the Lung Association in Toronto. For more information about radon and testing procedures, visit www.TakeActionOnRadon.ca.