[ RadSafe ] " Radon is invisible, deadly "
jaro-10kbq at sympatico.ca
Sat Jun 26 15:30:43 CDT 2010
Radon is invisible, deadly
By ANDRE FAUTEUX, Freelance June 26, 2010
Marie Bedard never smoked in her life. So she was doubly shocked to be
diagnosed with incurable lung cancer in the fall of 2007.
Two years later, Bedard read an article about radon in Touring magazine,
published by CAA-Quebec. Radon is a colourless, odourless and radioactive
gas that can seep into buildings, she learned, and has been recognized by
the International Agency for Research on Cancer as a direct cause of lung
cancer since 1988.
It's the second cause of the disease after smoking, and the first among
non-smokers who have been exposed to high concentrations for several years.
Radon levels are highest in the lower floors of buildings, and particularly
"Nobody had ever put me on that track," the 54-year-old accountant, said in
a telephone interview. "If Health Canada had widely publicized the dangers
of radon before 2007, I might not have developed an incurable lung cancer,"
said Bedard, the mother of a 17-year-old daughter. Bedard says she believes
her cancer was caused by exposure to radon.
When a test she ordered last winter showed the Quebec City bungalow where
she has lived since 1985 was accumulating huge concentrations of radon, she
quickly had the problem fixed. But it was too little, too late.
Radon is one of the principal naturally-occurring causes of cancer; others
include arsenic and mould. It is produced by the decay of uranium present in
soil, water and rock, and contributes more than half of the natural
radiation dose received by most people, according to the Canadian Nuclear
Association. Like man-made ionizing radiation (X-rays and nuclear power),
radon causes repeated and cumulative genetic damage by removing or adding
electric charges (ions) to our cells. Lung cancer is the only known health
risk of radon exposure.
Outdoors, radon levels are insignificant because the gas is diluted by air.
However, it can reach dangerous levels in confined spaces where it can
accumulate. Heavier than air, radon collects in the lowest and least
ventilated spaces: basements, crawl spaces and first floors (especially if
built on a slab). It mainly seeps in via dirt floors of crawl spaces as well
as through cracks and openings in foundation walls and concrete slabs.
No level of radon exposure is considered safe. "The risk of lung cancer
increases by 16 per cent per 100 Bq/m³ increase in radon concentration,"
according to the World Health Organization. The Quebec Department of Health
and Social Services calculates that 83.5 per cent of deaths caused by radon
result from lengthy exposures to concentrations below 150 becquerels per
cubic metre, which are most common.
In 2009, WHO recommended that all countries ideally adopt an actionlevel of
100Bq/ m³, or a maximum of 300 Bq/m³. Health Canada recommends work to fix
the problem be undertaken within two years if the average annual radon
concentration is between 200 and 600 Bq/m³ in the normal occupancy area of a
building. When the concentration exceeds 600 Bq/m³, it says, work should be
undertaken within 12 months. "When remedial action is taken, the radon level
should be reduced to a value as low as practicable," says the Health Canada
website. A radon test costs less than $100.
About 60 per cent of radon-related deaths occur in smokers, 30 per cent
among former smokers and 10 per cent among people who never smoked,
estimates the Quebec Department of Health and Social Services. "Like most
everybody, I was surrounded by smokers in my childhood," Marie Bedard told
The Gazette. "But since I'm allergic to smoke, I always kept my distance."
Health Canada says a non-smoker who spends his whole life in a home with
high radon levels has a five-per-cent risk of getting lung cancer. In the
same conditions, a lifelong smoker's normal risk (10 per cent) of developing
the disease more than triples, to 33 per cent -a Russian roulette of one in
The net result is that radon causes about eight to 10 per cent of the
country's lung cancer deaths, Health Canada estimates. In Quebec, it adds up
to an estimated 600 deaths annually. In comparison, an average of 628
Quebecers have been killed annually since 2004 in road accidents, which get
much more media attention. "We need TV campaigns on the dangers of radon
similar to those about drinking and driving," said Bedard.
Heavy exposure to radon was first statistically linked to a greater risk of
lung cancer in uranium miners. "There was data connecting residential radon
to lung cancer in the late '70s and early '80s," explains Don Fugler, a
senior researcher with Canada Mortgage and Housing Corporation. "But it was
not entirely clear to the health experts as to the degree of risk." Indeed,
the suspected risk of low residential exposures was only extrapolated in
1998 based on the risk of heavily exposed miners. And direct evidence of a
causal link in homes was only established in 2005.
But scientific uncertainty didn't prevent the U.S. Surgeon General from
applying the precautionary principle as early as 1988. That's when pediatric
surgeon C. Everett Koop declared radon a serious public health hazard. He
told Americans that the lowest levels of most buildings should be tested for
radon, or at least those occupied for four or more hours a day. "National
public service television ads to that effect began airing across America in
1990," confirms Dave Ryan, spokesperson for the U.S. Environmental
Similar TV ads by the Quebec Lung Association only began airing in Quebec in
2008, according to executive director Dominique Massie. Why not earlier?
Likely because Health Canada waited until 2007 to lower its acceptable limit
of radon in indoor air to 200 Bq/m³ of air. The Canadian guideline had been
800 Bq/m³ since 1988. That was the year the United States adopted a
residential guideline (or "action level" at which mitigation measures should
be undertaken) of about 150 Bq/m³.
Marie Bedard's bungalow was a rarity. The radon test revealed alarmingly
high radon concentrations: 967 Bq/m³ in the basement computer room where she
often worked and 920 Bq/m³ in her ground floor bedroom. "It is regrettable
that Health Canada waited until 2007 to lower its guideline to 200 Bq/m³, "
she said. "The United States have been aggressively recommending homeowners
test their homes for more than 20 years. It's dirt cheap, any homeowner can
afford it. Meanwhile, in Canada we let people die while waiting for
The Health Department counters that it recommended radon tests in the 1980s
and that it did its best to protect public health until a causal link was
established in 2005. "Health Canada encourages all Canadians to test their
home," explained Health Canada official Christelle Legault. "The guideline
in place since 1988 was established based on studies of risks for miners
exposed to radon in uranium mines. Health Canada also developed a guidebook
to help Canadians understand radon exposure in indoor air. Since then, our
staff has worked to increase the awareness of the risks of radon exposure
and the practical steps that can be taken to reduce exposure."
Legault added that the new Canadian guideline equals or surpasses that of
most major industrialized countries, which range between 200 and 400 Bq/m³.
"It is based on the risk to health, available mitigation technology and cost
to mitigate," she explained. In addition to respecting WHO's recommendation,
it applies to all buildings while the U.S. workplace guideline is 3,700
But Health Canada could have done more to inform all Canadians of the deadly
pollutant, says Jim White, former head of technical research at CMHC.
"Health Canada employees were told, about the time that I joined CMHC in
1981, to show that Canada did not have a radon problem. They did that. Of
course, it took some ingenuity.
"In the last year or two, they are more in line with other countries, but we
are not effectively telling Canadians about either mould or radon as risks
we should be doing something about."
White adds that builders' associations have repeatedly asked the government
not to tell Canadians about health risks in housing "because it would likely
affect their profit levels."
Untrue, counters Legault, Health Canada does not compromise public health by
prioritizing economic interests: "The health of Canadians is the priority."
Since 1995, the National Building Code has contained several requirements
intended to reduce infiltration of soil gases into homes. In 2005, the code
spelled out the need to ventilate basements and to seal slabs. However, few
municipalities enforce these provisions, except those with neighbourhoods
known to be radon hot spots, such as parts of Oka.
But the new Canadian radon guideline has created a sense of urgency. The
2010 NBC, to be published in November, will include more precautionary
measures that will become mandatory under Quebec's construction code for all
new housing in 2012, said Nancy Soulard, an official with the Regie du
Batiment du Quebec.
As for Marie Bedard, the alarming radon concentrations measured in her home
convinced her to hire Montreal engineer Yves Parent, who heads the
consulting firm RN Services.
Parent was trained in radon measurement and mitigation last year at the
University of Chicago. He is the first Quebec radon specialist certified by
the U.S. National Radon Safety Board. The NRSB and the National
Environmental Health Association are the only two radon certification bodies
recognized by Health Canada.
Parent's two-hour inspection of her house found minor air leaks that needed
to be sealed in her basement and garage. But her house also needed the most
effective method of preventing radon infiltration: sub-slab
depressurization. This typically means installing a perforated plastic pipe
horizontally in the crushed stone under a basement's concrete floor. The
pipe is then connected to a non-perforated vertical pipe going to the attic.
These measures and careful sealing of basements, which will be mandated in
the 2010 NBC, only cost about $500 when building a home. If a radon test
later reveals a dangerous indoor radon buildup, a special fan can then be
installed in the attic and connected to the piping to exhaust the radon
below the slab.
After the work on Bedard's bungalow, a test showed the radon level in her
basement had dropped to the lowest level possible: 19 Bq/m³. "I now live in
a healthy 21st-century home!" Bedard told The Gazette proudly.
"From the moment I learned about radon and its health consequences," Bedard
said, "it was a question of conscience. I had to measure the gas and make
any necessary repairs. On the one hand, I wanted to protect my daughter and
myself. On the other, I was a bit traumatized at the thought that at my
death, another family would suffer serious harm after buying my sick house.
That's why I put so much heart and energy into fixing it.
"Today, I'm proud of the idea of selling a radon-free house. I'll never
Not in my basement: A misleading myth
By ANDRE FAUTEUX, Freelance June 26, 2010
A dangerous myth holds that radon isn't a problem in most regions. "We still
don't know all the areas that are at risk," warns Dr. Jean-Claude Dessau,
head of the Quebec Department of Health and Social Services' radon
Any house can - and up to one in 20 Quebec basements do - accumulate
dangerous concentrations of the carcinogenic gas. The rate of radon
infiltration varies from house to house. It depends on soil conditions (the
amount of uranium present and cracks in the bedrock), house characteristics
(dirt floors in crawl spaces and slab perforations such as sump pump wells)
and even whether people use fans.
Radon hot spots
The most notorious hot spot is in the Lower Laurentians: Homes built on or
around Mont St. Pierre, in parts of Oka, St. Joseph du Lac and St. Andre
d'Argenteuil, sit on a dangerous uranium-rich geological formation. Radon
mitigation systems are mandatory in all new homes built in the area.
New hot spots are found these days as more people test their homes after
learning that radon is the second cause of lung cancer after smoking. Very
high levels have been measured in certain homes located in St. Hilaire on
Montreal's South Shore, for example. Based on a provincewide scientific
study of 900 homes conducted in 1992-1993 and on recent data, Dessau
estimates about 4.5 per cent of basements and 1.3 per cent of ground floors
exceed Health Canada's new radon guideline of 200 Bq/m³. Based on the 2006
Quebec housing stock (1.85 million single-family homes and duplexes), that
represents more than 83,000 basements and more than 24,000 ground floors
that are dangerous. These figures exclude other multi-family housing as well
as commercial, industrial and public buildings whose lower floors also
accumulate radon. The Quebec average residential radon level is 35 Bq/m3 in
basements and 16 Bq/m3 on ground floors, according to Dessau.
The Quebec Lung Association ( www.pq.lung.ca )sells radon test kits and,
when homeowners consent, it sends the results to the provincial Health
Often used by realtors, short-term radon tests lasting two to seven days are
the least accurate. Health Canada recommends that homes be tested using
long-term test devices, ideally for a minimum of three months during the
heating season. Radon levels are highest when homes are tightly sealed and
less ventilated. The test should be performed in the lowest part of any
building occupied more than four hours per day.
Health Canada recommends hiring firms trained in radon measurement and
mitigation that are certified by the National Environmental Health
Association and the National Radon Safety Board. Radioprotection and
Enviro-Option of Longueuil are the only two Quebec laboratories certified
for radon analysis.
Homes with low radon levels should be tested again after being extended,
Deschamps said. "Radon comes from the first few metres above the ground
under the house," he explained. "When you enlarge a house, the excavation
can make new portions of the soil more permeable to soil gases, including
For more information
Quebec firms certified in radon measurement
www.pq.lung.ca/environment-environnement/radon and mitigation:
Quebec Department Health and Social Services: www.msss.gouv.qc.ca
Health Canada: Radon, A Guide for Canadian Homeowners:
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