Radon has been lurking in the ground for centuries, but only recently has it been recognized as an environmental danger.
In 1984, a Pennsylvania construction engineer working on the site of a new nuclear power station became concerned when his body continued to trigger workplace detectors-not when he was leaving work but as soon as he arrived each day. To everyone's surprise, it was found that he was being contaminated not at work but at home by high levels of radon.
A gas produced by the natural decay of uranium, radon is widespread on the surface of the earth and now recognized as a serious environmental threat by the Centers for Disease Control, the American Lung Association and most other health organizations. The second leading cause of lung cancer, radon is believed to be responsible for about 14,000 deaths a year.
The radon levels in me Pennsylvania engineer's home were several thousand times that found in the average American building. He and his family had a risk for lung cancer equal to that of someone smoking 135 packs of cigarettes a day.
Any exposure, however, is considered harmful, particularly if it's combined with other risk?, .such as exposure to tobacco smoke or industrial carcinogens.
The air outside normally has about 0.4 picocuries per liter (pCi/L). The same amount breathed all day in a building is more hazardous, and, in fact, the average home has a much higher level-1.25 pCi/L. The U.S. Congress in 19 88 set a long-term goal of reducing radon levels in homes to no more than the outdoor level.
Studies Confirm Danger
Although it's difficult to be concerned about a substance you can't see, taste or smelt, the danger of radon has been confirmed through extensive research.
Studies involving thousands of miners followed for up to 30 years consistently found that those exposed to radon had an increased incidence of lung cancer-even if they were non-smokers and had not been exposed to other workplace hazards such as asbestos, silica, diesel fumes, arsenic, chromium, nickel or ore dust.
The increased incidence has been found even in miners exposed to relatively low doses (in the range of 4 pCi/L). Long-term exposure at this level, in fact, was found to be more hazardous than short-term exposure at a much higher level.
Laboratory animals exposed to the gas had shorter life spans and significantly higher rates of lung cancer, pulmonary fibrosis and emphysema.
Based on these studies, a panel of world experts convened by the World Health Organization concluded in 1988 that radon causes cancer in both humans and animals. A 1991 National Academy of Sciences report concluded that the effective doses per unit of exposure for people in their homes should be about 30 percent less man for miners.
The Environmental Protection Agency, the U.S. Surgeon General and the American Medical Association recommend that every home be tested for radon. And if the level exceeds 4 pCi/L, prompt steps should be taken to reduce the hazard.
Radon is a danger in every part of the country, and scientists believe that it exists at somewhat high levels in one of 16 American homes. These include homes of all types-old homes and new homes, drafty or insulated, those with and those without a basement. Even if your neighbor's house has been given a clean bill of health, that doesn't mean your house is safe.
What's the radon level in your home?
Inexpensive do-it-yourself tests are available by mail order or at many retail outlets. Look on the label to be assured the test kit is "qualified" or state-certified. You can also hire a state-certified contractor to test and, if necessary, make changes.
For a short-term test, it's necessary to close all windows and doors for 12 hours before and then for two to three days during testing. The test kit is to be placed in a room used regularly on the lowest level of your home. When completed, the test is mailed to a lab for analysis.
If the test reveals a radon level of 4 pCi/L or higher, then a repeat test should be performed-either another short-term test or a long-term test, which remains in your home for more than 90 days. The long-term test gives a better picture of radon levels throughout the year, but if the first test is significantly higher than the recommended level, then the follow-up test should be a short-term one so there's no delay in fixing the problem.
The cost of repairing a radon problem is $500 to $2,500. Radon exists in the soil, and it is drawn into homes because of the relatively lower air pressure inside. As a result, repair usually means sealing cracks in the foundation and installing a ventilation system that normalizes the air pressure.
In most cases, radon reduction systems work quite well, often cutting the exposure in half or even by as much as 99 percent.
New homes can be built with radon protection, but that doesn't ensure that a problem won't eventually develop. The U.S. Surgeon General recommends testing every two years and any time you make structural changes or occupy a previously unused level of your home.
Radon can also enter your home through water, particularly if the source is a well or a public water supply using ground water. The danger from water is much less, however, and comes mainly from inhaling the radon when the water is used for showering or boiling hot water.
If you've avoided radon testing because you're afraid a high level will lower the selling price of your home, don't worry. Many potential buyers will inquire about radon testing, and the house may actually have a greater value if you can show that the radon level is low or that the problem has been fixed.
Even if you've lived with radon in your home for many years, it's never too late to reduce your exposure. If you smoke, of course, or have been exposed to occupational pollutants, your risk is multiplied. The sooner you take action, the better.