Good Science in Plain Language

Radiation Induced Cataracts

Radiation Induced CataractsOne of the potential long-term effects of radiation exposure is the development of cataracts. Cataracts are a deterministic effect of radiation exposure, meaning that there is a threshold dose below which you would not expect to see cataracts, and above which you would. The severity of the cataract would then increase with increasing exposure.

The International Commission on Radiological Protection (ICRP) has recently updated its estimate on the threshold dose, decreasing it to 500 mGy to the lens of the eye, and now recommends an equivalent dose limit for the lens of the eye of no more than 50 mSv in a single year, and no more than 100 mSv in a defined 5 year period.

For more information on radiation induced cataracts, visit the IAEA Cataract Study.

Last X-Ray Safety Officer (XSO) Training for 2011

The last X-ray Safety Officer Course (XSO) for 2011 is taking place November 15-17 at the beautiful Sutton Place Hotel in Toronto. If you are responsible under provincial and federal regulations for the safety of employees exposed to X-rays in the workplace, the Radiation Safety Institute of Canada offers this 3-day course, which has been awarded 1,0 maintenance points by the Board of Canadian Registered Safety Professionals.

For full details regarding your legal obligations, as well as the subjects covered, visit the “Your Workplace” tab above and look under our “Education and Training Services” section for “Professional Certificate Courses”

Dr Oz Talks about Radon and Lung Cancer

Are you and your family at risk of developing lung cancer? The connection between lung cancer and exposure to radon gas took central stage at the Dr. Oz Show on February 9, 2011.

The segment, called #1 Cancer Risk in your Home brought to light the dangers of long-term exposure to radioactive radon and the uncomfortable truth about how wide-spread the problem really is.

Dr Oz brought to his audience expert opinion, research and recommendations from the leading national and international organisations working to raise awareness on this important public health issue.

If you watch the show you will learn:

  • radon is a Class A carcinogen. It is the second leading cause of lung cancer among smokers and the first leading cause lung cancer in non-smokers
  • radon is a naturally occurring, colourless, odourless, highly toxic gas
  • radon may seep into your home and, when trapped indoors, may become a serious health hazard
  • one in every 15 homes in the US has high radon levels
  • the only way to know how much radon you have  in your home is to get your home tested
  • mitigation does not have to be complicated or expensive

Radon is not constrained by borders and many of the points made by Dr Oz are universally applicable. Though national statistics may vary between countries, there is no doubt that, wherever you live, the single most important step you can take today to protect your family is to get your  home tested.

Please remember: because radon levels may fluctuate over time, for an accurate result the Radiation Safety Institute of Canada and Heath Canada recommend using a 90-day, long-term test.

You can watch the full episode by following this link: The Dr. Oz Show

For more information on radon and to purchase a test please  click here.

Home radon testing is simple and inexpensive.  Don’t put it off, do it today!

Cross-Canada Survey of Radon Concentrations in Homes: 1st Year Results

In 2010 Health Canada finished the first phase of a nation-wide survey of radon concentrations in Canadian homes. The whole project is being implemented in two phases and will take two years to complete. During this period approximately 18,000 homes will be tested.  The survey results will contribute to the creation of a radon map of Canada and will help us better understand the geographic distribution of  radon levels across the country.

homeThe survey participants are being randomly selected across all provinces and territories. Participation in this study is 100% voluntary. Home owners are being recruited over the phone and offered a long-term (90-day) do-it-yourself radon test.  The results of the tests are then being analysed and communicated to the home owners, along with the  remediation information, where necessary.

Analysis of the first phase data was completed last year, after approximately 9000 homes were tested during the fall-winter of 2009/2010. The first year survey results have been tabulated and can be found summarized in the table below. The table was prepared by Health Canada and contains information on the percentage of participants in each province/territory and the respective results. In order to better understand the table,  keep in mind that Health Canada recommends that remedial action be taken where radon levels exceed 200 Bq/m3.

Year Radon Results by Province and Territory

Province / Territory Below 200 Bq/m3 200 to 600 Bq/m3 Above 600 Bq/m3
AB 93.1% 6.5% 0.4%
BC 95.4% 3.9% 0.7%
MB 76.5% 22.1% 1.4%
NB 83.0% 11.7% 5.3%
NL 94.7% 4.4% 0.9%
NS 91.8% 6.3% 1.9%
NT 96.0% 4.0% 0.0%
NU 100.0% 0.0% 0.0%
ON 95.1% 4.3% 0.6%
PE 95.5% 4.5% 0.0%
QC 91.0% 8.3% 0.7%
SK 84.2% 14.2% 1.6%
YT 84.1% 10.6% 5.3%

* Source: Health Canada, Environmental and Workplace Health/Cross-Canada Survey of Radon Concentration in Homes (2010), see:

What Does this Mean for You?

Please keep in mind that whether or not higher than 200 Bq/m3 radon levels were registered in your province, there is no other reliable way to know the actual radon level in any individual building than testing. If nothing else, the first year survey results only reinforce the importance of testing your home for radioactive radon gas.

To learn more about the Cross-Canada Radon Survey,  please visit the Health Canada website.

To learn more about the Institute’s radon testing service, go to our Home Radon Testing page.

Some Facts About Dirty Electricity

“Dirty electricity” is being blamed by some for a host of symptoms from headaches, sleeplessness, and general pains to cancer and suicide. “Dirty electricity” is said to be caused by a variety of electrical devices, dimmer light switches, and compact fluorescent light bulbs. It should be noted that “dirty electricity” is not actually a scientific term. It refers to electricity that has been transformed or “corrupted.” It is measured as the noise caused by harmonics in an electrical system. Some that purport it to be a health concern offer a solution in the form of filters that can be plugged into a home’s outlets to reduce the signal from these harmonics thus reducing the level of “dirty electricity” in a home.

But let’s see what experts at the World Health Organization, Health Canada, and more are saying about “dirty electricity”.

Quotes from the WHO

  • Conclusions from scientific research
    In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research.
  • Effects on general health
    Some members of the public have attributed a diffuse collection of symptoms to low levels of exposure to electromagnetic fields at home. Reported symptoms include headaches, anxiety, suicide and depression, nausea, fatigue and loss of libido. To date, scientific evidence does not support a link between these symptoms and exposure to electromagnetic fields. At least some of these health problems may be caused by noise or other factors in the environment, or by anxiety related to the presence of new technologies.

Quotes from Health Canada

Health Canada looked into the efficacy of Stetzer filters which are purported to reduce the amount of “dirty electricity” in a home. Here is what they concluded:

The Stetzer filter does not clean up line voltage harmonics. Nor does it help to restore the current of a non-linear load back to a sinusoidal shape. The Stetzer filter current is highly distorted containing harmonic content up to 10 kHz. (Stetzer current harmonics are accentuated versions of the line voltage harmonics.) Since Stetzer filter currents add vectorily to the other load currents in the home, their distortion products (harmonics) are carried on the electricity supply and add to the level of “dirty electricity” in the house.

The Stetzer filter is probably effective in attenuating high frequency (4kHz to 100 kHz) noise on the AC power lines although these components are small to begin with. No assessment can be made concerning its effectiveness in suppressing transient disturbances since these phenomena are random, infrequent events for which we are unable to test.

Gajda et al, “Report on Evaluation of Stetzer Filters”, Consumer and Clinical Radiation Protection Bureau, Health Canada, May 11, 2006

Read more about EMF and its effects on the body.

Airport screening and backscatter x-ray scanners – should you be concerned?

airport_security_scannersThere has been a lot of news in recent days about the new security measures in airports following the incident onboard Northwest Airlines flight 253 on Christmas Day 2009. As a result, some airports have started using new full body scanner technologies, such as backscatter x-ray scanners and millimeter wave scanners. This has led to concerns in the public about potential health effects, but is there any reason to be concerned about radiation exposure?

The first thing you need to know about these scanners is that the two technologies are very different. Whereas backscatter x-ray scanners use x-rays to image, and being exposed to high levels of x-rays can lead to adverse health effects, millimeter wave scanners use waves of much, much lower energy, and will not lead to adverse health effects. Learn more about the differences between the technologies and how to recognize them here (coming soon).

We will focus here on backscatter x-ray machines. To understand the potential risks, it is important to know what backscatter x-ray scanners actually are and what they do. These machines use x-rays to give security personnel an image of the exterior of a passenger’s entire body. The idea is to reveal anything someone is carrying under their clothes, particularly liquid explosives, weapons, and drugs.

These scanners are similar to medical x-ray machines only they operate at a much lower energy. This means that the radiation dose a person would receive from a backscatter x-ray scan would be much lower than the dose received from a medical x-ray. Another difference is that in medicine, the radiation that passes through your body is used to create the picture. Backscatter technology uses the x-rays that scatter (or “bounce”) off the surface of your body, as well as any objects next to it, to create the image. There is more detailed information about this technology on the website of American Science and Engineering (AS&E), the manufacturer of these scanners.

The health risks for air travellers from this technology is negligible. Whenever radiation is concerned, people are most often concerned about increasing the risk of developing cancer. AS&E states that the dose delivered to a passenger is less than 0.1 micro sievert (µSv) per scan. A µSv is a unit used for measuring radiation dose. A typical dental x-ray can deliver a dose of 0.01 milli sievert (mSv) to a patient. That’s 10 µSv. In other words, it would take 100 backscatter x-ray scans to deliver the same radiation dose as a dental x-ray. In fact, the National Council on Radiation Protection and Measurements (NCRP) of the United States says that 0.01 mSv of radiation dose per year is a negligible dose to an individual.

The sun and radioactive materials naturally occurring in the Earth as well as in the air all contribute to our overall radiation dose. In fact, each of us receives about 3 mSv per year from natural “background” sources of radiation like the sun. Indeed, when flying on an airplane, the average passenger receives a higher radiation dose than those traveling by ground. How much more? There are many factors that affect the dose, but a low estimate is that for every hour flown in a commercial airliner, passengers receive a dose of 3 µSv per hour. So, one hour of flight is roughly equivalent to 30 backscatter x-ray scans.

For more information, please see the following:

Protecting your family from radon gas

As Canadians, we all want the cleanest, safest, most secure home environment to live in and raise our families. One way to do this is to monitor our homes for the quality of the air we breathe. Radon gas is not something we hear about every day in Canada however, radon exposure is a leading cause of lung cancer – second only to smoking.

Radon is a radioactive gas present in the soil and rocks around and beneath your home. Radon gas enters your home through cracks and gaps in floors and walls. It can be an issue in all types of homes: new or old, with finished or unfinished basements, regardless if they’re heavily sealed or drafty. While problems can be more concentrated in some areas of Canada, any home can be at risk.

Radon is the second leading cause of lung cancer in Canada

Radon is the second leading cause of lung cancer in Canada

While all Canadians should be concerned about the level of radon gas in their homes, it appears smokers are at a higher risk of developing lung cancer because of their exposure. In fact, the combined effects of radon exposure and smoking create a risk greater than the two separately. However, non-smokers are not immune: radon exposure is the leading cause of lung cancer in this population segment. In Canada, long-term exposure to radon causes around 2000 deaths every year.

There is nevertheless a bright side to all of this: a home with radon problems can be fixed, and the costs of repair are often low. But first, you need to find out if your home is affected by high concentrations of radon.

Testing your home’s radon levels is the key and the good news is – it’s easy. Radon is measured in units called “becquerels per cubic meter (Bq/m3)”, and the Government of Canada’s guideline for radon in indoor air is 200 Bq/m3. Health Canada recommends that steps be taken to reduce radon levels in any home that tests above the guideline. Inexpensive commercial testing units are available at retailers, radon testing service providers and from on-line and telephone distributors across Canada. Health Canada recommends a minimum three-month testing period to maximize testing accuracy and be able to estimate your annual average level. The most popular long-term radon detectors are the electrets and the alpha track detector. These devices are placed in a home and exposed to its air for a specified period of time, and then the testing kit is sent to a laboratory for analysis.

If your test’s result is above 200 Bq/m3, then you need to take action, but there’s no need to panic. Because health risks occur only after long-term exposure, Health Canada provides timelines for homeowners to remedy a radon problem. If your home’s radon levels are between 200-600 Bq/m3, then you should remediate your home to lower the radon level below the guideline within two years. If your home’s radon concentration is above 600 Bq/m3, then look to remedy that within a year.

Some quick and easy steps you can take that may help reduce radon levels in your home include:

  • Renovating existing basement floors, particularly earth floors.
  • Sealing cracks and openings in walls and floors, and around pipes and drains.
  • Ventilating the basement sub-floors.

There is a wealth of information about radon on Health Canada’s website, at, including information on how to obtain a free booklet called Radon – A Guide for Canadian Homeowners. Knowing the risks of radon and testing your home for radon will go a long way towards ensuring a safe home for you and your family.

Ontario Lung Association warns of radon risks

As winter weather approaches and we move activities indoors, it’s a good time to think about the quality of the air in our homes. Radon is a colourless, odourless gas that is produced from the natural breakdown of uranium in rocks and soil. Radon can enter a home through tiny openings in floors and foundations and build up to dangerous levels.

ola-postLong-term exposure to radon is the second leading cause of lung cancer in Canada. For smokers, the risk of developing lung cancer from radon exposure is even higher. Brian Stocks, air quality manager for the Ontario Lung Association, says the association is partnering with Health Canada “to raise awareness about the health effects of long-term exposure to radon gas and to promote the testing of homes. By learning about the health risks associated with radon and how to test your home, you can protect your family.”

Radon is found across Canada and any home can be at risk. The level of radon in a home depends on many things, including the amount of uranium in the soil, the number of entry points into the home, and the type and level of ventilation. Radon levels can vary between neighboring homes and even within a home from day-to-day. The only way to know if your home has high radon levels is to test. Health Canada recommends long term testing, for a minimum of three months, between September and April, when doors and windows are typically closed.

Radon testing is easy and inexpensive. Radon test kits can be purchased from major home supply stores such as Home Hardware (if not on the shelf, ask them to order you one) and Wal-Mart. Test kits can also be ordered on-line from organizations such as the Radiation Safety Institute. While both short-term and long-term tests are available, long term testing is recommended to get a more accurate indication of the annual average exposure to radon.

Once you have purchased the test kit, follow the instructions and place the detector in a suitable location. Testing should be done in the lowest area of the house where your family spends more than four hours per day (e.g. a basement bedroom, or lower-level family room). When the testing period is over, simply return the detector in the self-addressed envelope included with the kit. You will receive a report telling you how much radon there is in your home. Health Canada’s guidelines recommend that you take action to reduce the radon levels in your home if the test results are above 200 Bq/m3 (or approximately 4piC/L which is the American unit of measurement).

You can obtain a copy of Health Canada’s brochure, Radon: What You Need to Know, from the Ontario Lung Association by calling 1-888-344-5864, online at, or from Health Canada by calling 1-800-O-Canada. A guide called Radon: A Guide for Canadian Homeowners is also available from the Canada Mortgage and Housing Corporation –

WHO slashes radon limit in homes, cites lung cancer risks

who-logoGENEVA (Reuters) – The World Health Organization (WHO) has drastically cut the maximum amount of radon, a naturally occurring gas, that should be permitted in homes because of strong evidence it causes lung cancer.

In a WHO Handbook on Indoor Radon issued quietly on Monday, it called for public health authorities and the construction industry to make great reductions in exposure to radon, calling it a “major and growing public health threat in homes.”

Radon is a cancer-causing radioactive gas that humans cannot see, smell or taste. It arises from the natural decay of uranium and can seep into homes through cracks in basements or cellars.

“Radon is the second most important cause of lung cancer after smoking in many countries,” said Dr. Maria Neira, director of WHO’s public health and environment department.

Most radon-induced lung cancers occur from exposure to low and medium doses in residential buildings, she said in a statement on the handbook, drawn up by more than 100 experts.

Policy makers and the construction industry must reduce exposure to radon through tougher building codes for new homes and mitigation programs for existing ones, she said.

The WHO’s new recommended maximum level of radon gas is 100 becquerels per cubic meter — one tenth of its previously recommended maximum of 1,000 becquerels, issued in 1996.

If a country cannot meet the new standard, levels should not exceed 300 becquerels per cubic meter, it said, noting that the risk of lung cancer rises 16 percent per 100 becquerels.

“Recent studies on indoor radon and lung cancer in Europe, North America and Asia provide strong evidence that radon causes a substantial number of lung cancers in the general population,” the 110-page handbook said, referring to countries including Britain, Canada, China, France, Germany and the United States.

An estimated 3 to 14 percent of lung cancers are attributable to exposure to radon, it said.

Many countries are aware of the risks associated with radon and have already reduced their maximum allowed levels to 200-400 becquerels, according to WHO expert Dr. Ferid Shannoun.

“Studies show that radon is the primary cause of lung cancer among people who have never smoked,” the WHO said.

People who smoke or who have smoked in the past suffer higher levels of radon-induced lung cancers because of a “strong combined effect of smoking and radon,” it added.

Higher radon concentrations can be found in mines, caves and water treatment facilities, according to the Geneva-based WHO.

“Radon gas enters houses through openings such as cracks at concrete floor-wall junctions, gaps in the floor, small pores in hollow-block walls and through sumps and drains,” it said.

Levels can be lowered through very effective yet relatively inexpensive techniques such as sealing cracks in floors and walls and increasing the ventilation rate of the building.

Institute Officials Stress Awareness and Education in Debate about Dose Limits


September 2009 Edition of OHS Canada magazine

Officials from the Radiation Safety Institute were recently interviewed for a major feature article which appears in the September 2009 edition of OHS Canada Magazine.

The story, by assistant editor Dan Birch, looks at the implications of “Exposure to Radiation and Health Outcomes” – a new review which recommends changing the dose limits meant to protect workers from radiation.

The review, conducted by Saskatoon-based researcher Mark Lemstra, and jointly commissioned by the Canadian Centre for Policy Alternatives and the Saskatchewan Union of Nurses, is seeking lower dose limits for Canadians in the workplace.

The Institute’s President and CEO, Dr. Fergal Nolan and Dr. Richard Link, Chief Scientist, were asked to provide the Institute’s views on both the report and the issue of radiation safety in the workplace in general. Dr. Nolan described the circumstances in which the Institute was founded, particularly the incidence of lung cancer in uranium mine workers in the 1970s and 1980s in Elliot Lake, Ontario.

This was contrasted with today’s advanced state of safety in the uranium mines operated by Cameco Corporation and Areva Resources Canada in Northern Saskatchewan.

While acknowledging that most employers are making good progress, Dr. Nolan and Dr. Link both expressed concern with state of X-ray safety regulations in most provinces, particularly in Ontario. To read the full issue online, you must subscribe to OHS Canada Magazine. Please contact us directly to obtain a copy of this article.


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