Podcast Title: Health and Safety to Go!

Episode #125:  Recognizing Radon

Introduction Welcome to Health and Safety to Go, broadcasting from the Canadian Centre for Occupational Health and Safety.

Host:  Hello and welcome to this episode of Health and Safety to Go. In Canada, November is Radon Action Month. To tell us about radon, what it is, where it’s found, the impact it can have on our health and how we can limit our exposure to it, we welcome Dr. Cheryl Peters, Postdoctoral Fellow at Carleton University and Occupational Exposures Lead Scientist at CAREX Canada.

Thank you for speaking with us today Dr. Peters.

Dr. Peters: Thanks for having me.

Host:  So Dr. Peters, could you start by telling us exactly what radon is?

Dr. Peters: Sure, Radon is a colourless, odourless, and tasteless gas released when uranium, which is found naturally in rocks and soil, decays. This gas emits radioactive particles that can be inhaled and may lead to cancer.

Radon is classified as a known carcinogen by the International Agency for Research on Cancer. It is the leading cause of lung cancer among non-smokers. Health Canada estimates that radon is responsible for approximately 16% of lung cancer deaths in Canada, which translates to more than 3,200 deaths per year.

People who smoke and are exposed to elevated levels of radon have an even higher risk of developing lung cancer.

Host:  And where can we find radon?

Dr. Peters:   Well basically everywhere. In Canada, radon can be found in new homes, older homes, in public buildings, such as hospitals, schools, long-term care facilities, as well as underground worksites, such as mines. Radon levels are significantly higher in indoor air than in outdoor air.

Host: How does the radon get into the buildings?

Dr. Peters:  Radon gas enters buildings when the air pressure inside is lower than in the soil surrounding the foundation. This pressure difference draws air and other gases, including radon, into buildings through cracks and openings in the foundations construction joints, gaps around pipes, or sump pumps and drains, through windows, or even through cavities inside walls. This is why underground mines can have particularly high levels of radon, because they are in direct contact with rocks and soil that are the source for radon.

Radon concentrations vary depending on local geology, on soil and building characteristics as well. The highest concentrations are found in areas with uranium and thorium which is another radioactive metal.  These ore deposits and in granite formations which have naturally higher concentrations of uranium.

Host:  How widespread is the presence of radon?

Dr. Peters:  Most Canadian homes and buildings contain at least some level of radon gas. In a cross-country survey of radon concentrations that was done about 5 years ago, in about 14,000 homes done by Health Canada, around 7% of the homes tested had indoor radon concentrations above the current Canadian household guideline, which is 200 Bq/m3 of air. Radon levels vary significantly across the country however. There are a number of regions where indoor radon is more prevalent, but we can’t say that any area of the country is ‘radon free’. Saskatchewan, Manitoba, New Brunswick, and the Yukon had the highest percentages of participant homes in that survey that tested above the radon guideline.

Host:  How can you detect radon and measure it?

Dr. Peters:  The only way to know if radon gas is present is to test for it.

Radon detectors are small devices placed in the home or workplace for a specified period of time and then sent to a laboratory for analysis.

Because radon levels vary over time, and sometimes quite dramatically, Health Canada recommends using a long-term detector and testing for a minimum of three months, over the winter months if possible because homes tend to be sealed and ventilation is lower. The most popular long-term detectors filter air from your home or workplace through the device and measure particles that are released when radon decays.

Radon testing is available through certified service professionals; lists of these are available through the Canadian Association of Radon Scientists and Technologists (CARST) and the Canadian National Radon Proficiency Program (C-NRPP).

Homeowners can also purchase do-it-yourself kits through their local Lung Association or even at hardware stores, and just follow the guidelines outlined by Health Canada, and included in their kit, for how to properly conduct a radon test.

Host:  How does radon affect us in the workplace?

Dr. Peters:  CAREX Canada results show that approximately 188,000 Canadians are expected to be exposed to radon at work. The workers at risk of the highest exposure to radon are people who work in underground mines, as I mentioned before.

Indoor workers, including those who work in elementary and secondary schools, or in public administration, government, banks and credit unions, for example, can also be exposed to radon. This would include occupations like office clerks, school teachers, janitors, caretakers, just anyone who works in an indoor environment.

Results from the Burden of Occupational Cancer project, which is a related project of CAREX Canada show that approximately 190 lung cancers are attributed to occupational radon exposure each year in Canada.

Host:  Are there specific areas of work that are more susceptible to exposure?

Dr. Peters:  For sure, so as I noted earlier, radon levels are significantly higher in indoor air than outdoor air.

Radon levels can be higher in rooms that are closer to the ground, such as basements, but in some cases high radon levels can be found in any area of a workplace. Concentrations of radon are also often higher in confined spaces or underground - especially in mines.

Radon levels in buildings also vary across the season, and they can change significantly in 24 hours (by a factor of two or three). As I have alluded to before, the highest levels usually occur in winter because windows and doors are kept closed in Canada, and the sealed buildings and therefore decreases ventilation. Sealing buildings to conserve energy can result in higher levels of radon as well.

Again, the only way to know if you’re actually being exposed to radon gas is to test for it. If a worker has concerns about radon levels in their workplace, they can request a radon test. Employers should be aware of and recognize the potential for radon exposure.

Host:  What can we do to reduce the risk of exposure?

Dr. Peters:  Well a few things.  If your home tests above the recommended guideline, you should hire a certified radon professional to determine the best and most cost effective way to reduce that radon level. For workplaces, it’s a bit different.  The acceptable level differs across jurisdictions or provice, and you should talk to your employer or union if you’re concerned about radon exposure.

There are few things you can do to reduce worker exposure however:

• You can try to use raw materials that are low in naturally occurring radioactive materials.  This would be, if we are thinking about putting a granite countertop in our home, we can try to get one that has less radon being emitted from it.

• We can design and construct, or modify buildings to prevent radon entry through the soil gas or facilitate its removal.

• You can increase air circulation by regularly opening your windows or by installing mechanical ventilation.

• You can reduce the time spent by workers in areas where excess radon may be present.  Maybe this is not having offices in basements.

• In situations where people are exposed to very high levels of radon, you can use NIOSH-approved respirators for radionuclides and radon daughters, if administrative controls are not enough to reduce levels to an acceptable level.

The specific methods used to remove radon from existing buildings depend on several factors, including the building concentration and the soil type. The most effective of these methods is called “active sub-slab depressurization”, which is a simple way to say a remediator installs a pipe through the floor slab of the foundation. This pipe is attached to a fan that runs continuously and draws radon gas out from beneath the home or workplace, to the outdoors where it is effectively diluted.

You can find other remediation approaches in Health Canada’s Radon Reduction Guide for Canadians. And I also want to reiterate that testing for radon during the colder months is a good time, since we tend to seal up our living spaces to keep the cold out and therefore reduce fresh air circulation and ventilation, allowing radon to build up to higher levels.

Host:   Thank you for joining us today Dr. Peters and sharing your expertise. I for one am going to get my home tested for radon as soon as I can.

Dr. Peters:  Thank you.

Host:   For more information on radon and many other workplace health and safety topics, please visit ccohs.ca.