Riled about radon

Health officials in Canada are much less concerned about the contamination of homes with cancer-causing radon gas than their international counterparts. Could this complacency be killing Canadians?

By: Janice Hamilton
 

Radon has been fingered by several leading U.S. health and science organizations as the second leading cause of lung cancer after smoking

  It's colourless and odorless, and Canadians know very little about it. But radon - a naturally occurring gas - can be deadly.
  Radon has been fingered by several leading U.S. health and science organizations as the second leading cause of lung cancer after smoking. It may be poisoning you silently from the ground beneath your house - seeping from the soil into your home's air supply. This happens often enough that American health experts (unlike their more sanguine Canadian counterparts) have labeled radon a serious public health problem.
  Here's how the process works: Radon comes from the natural radioactive breakdown of uranium, an element often found in granite, shale and phosphate rocks. Radon gas percolates up through the soil and into basements through cracks or sumps where it can build up to hazardous concentrations. It can also get into the air if contaminated well water is heated or agitated.
  Radon quickly decays into so-called daughter particles. If you breathe them in, they continue to decay in the lungs, damaging the fragile tissues. The U.S. Environmental Protection Agency (EPA) estimates that radon causes about 14,000 lung cancer deaths a year. Smokers who are exposed to high levels of radon are at greater risk of developing lung cancer than non-smokers.
  These health hazards have created a heightened state of alert in the U.S., where its more common for homeowners to test for radon, and to take measures to eliminate it if the gas if found to be present.
  The lower level of concern in Canada may have something to do our health officials' higher threshold of tolerance for the gas. The Canadian government believes no remedial action needs to be taken until radon concentrations reach a level of 800 Bq/m3 (becquerels per cubic metre) or 20 pCi/l (picocuries per litre).
  By contrast, the U.S. EPA identifies a range of intervention levels, and red flags start to go up at only one-fifth of the way towards the Canadian danger zone - at 150 Bq/m3, or 4 pCi/l.. The World Health Organization's safe exposure guidelines are also five times lower than Canada's. According to Ian Morton, director of environmental health for Pollution Probe, the high Canadian guideline "automatically means we won't have a problem with compliance."
  Surveys done in the 1970s and '80s estimated about 0.01 per cent of Canadian homes have levels higher than 20 pCi/l, while four per cent exceed 4pCi/l (the level at which U.S. authorities start to get concerned).
  Radon is more common in some areas than others. For instance, you may have little cause to worry if you live in Montreal or Vancouver. Yet Winnipeg, Regina, Sudbury, Fredericton and Halifax tend to have more radon. There are also problems in B.C. Interior communities such as Nelson. As well, it's impossible to predict which buildings are affected: one structure may have a radon problem, while a neighbouring house is fine.
  The likelihood that your home has dangerous radon levels is very low, but the only way to know for sure is to use a commercially-available detection kit costing about $30. The U.S. government recommends all homes below the third floor be tested for radon. The most popular radon detectors, such as charcoal canisters, are exposed to the air for several days and then sent to a laboratory for analysis. If you can't find a testing kit locally, you can order one from the United States.
  If a radon problem does exist, chances are you will be able to solve it inexpensively by sealing cracks in basement walls or covering drains. If that doesn't work, a ventilation system to pump the gas out from under the house may be necessary. That could cost several thousand dollars. To avoid problems in a new home, an impermeable plastic sheet can be laid down before the concrete slab is poured.
  Meanwhile, Pollution Probe wants Health Canada to revise radon guidelines and introduce preventative programs. It suggests homeowners be required, as a condition of sale, to tell purchasers whether the home has had a radon problem and what has been done to eliminate it.

Janice Hamilton is a Montreal writer specializing in science and health issues.

Get More/Do More
The following websites have more information on radon gas and what you can do to combat it:

  www.epa.gov/iaq/radon - A radon guide prepared by the U.S. EPA.
  www.hc-sc.gc.ca/ehp/ehd/catalogue/general/iyh/radon.htm - Basic information from Health Canada.
  www.hc-sc.gc.ca/ehp/ehd/catalogue/rpb_pubs/radon.htm - Check out the booklet, Radon: A Guide for Canadian Homeowners, 1997, prepared by Health Canada and the Canada Mortgage and Housing Corporation.
  www.hlth.gov.bc.ca/rpteb/radon001.html - Data from the B.C. government on radon levels in homes and schools there.
  www.remradon.com/homebuy.htm - An informative site from a U.S. radon testing company.

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