Radon Link in 21,800 Deaths a Year

by Paul Recer, AP Science Writer
Copyright 1998 The Associated Press
Associated Press (February 19, 1998)

WASHINGTON (AP) -- Radon, a natural radioactive gas that collects in some homes, is linked to about 21,800 American lung cancer deaths a year, researchers said Thursday. Most of the victims were smokers.

``Radon, particularly in combination with smoking, poses an important public health risk and it should be recognized as such,'' said Dr. Jonathan Samet, a Johns Hopkins University professor and chairman of a National Research Council radon study committee.

Exposure to radon at any concentration, Samet said Thursday at a news conference, ``carries some risk of lung cancer,'' and as a result, the gas ``is an important public health problem.''

Although the NRC committee carefully avoided taking a policy position, the report adds weight to a recommendation from the Environmental Protection Agency for radon testing in homes and for venting of houses that have high levels of the radioactive gas.

Americans have spent an estimated $400 million on radon testing and renovation since the gas was first linked to lung cancer in the 1980s. The NRC committee said about 6 percent of American homes have radon concentrations above the EPA recommended minimum.

The NRC report does little to settle a controversy about just how dangerous radon gas is in the typical home. Some research, such as a 1996 Finnish study published by the Journal of the National Cancer Institute, has found that even at high concentrations radon poses, at most, only a very slight risk.

Radon gas comes from the decay of uranium and radium in soil and rocks. Leaking from the earth, it can collect in houses or basements.

When inhaled, the gas can leave in the lungs Alpha particles that emit low levels of radiation over long periods of time.

Members of the NRC committee admitted that they could not agree upon a minimum threshold of risk for radon, noting that even the smallest possible exposure, a single Alpha particle, can have a theoretically damaging effect if inhaled into the lungs.

``A single Alpha particle is capable of producing quite profound damage,'' said one committee member, Dr. Eric Hall of Columbia University in New York. The committee noted that lung cancer can result from damage to a single cell.

The committee concluded that about one-third of the nation's radon-related lung cancer deaths could be prevented if radon levels in all homes were reduced to at least 4 picocuries per liter of air (a measure of radioactive decay), which is the EPA recommendation.

The report's conclusions differ little from an NRC report issued in 1991, but Samet said the new work is based on much more extensive research and a ``much richer data base.''

He said the committee analyzed 11 studies on the effects of radon among hard rock miners, the occupational group with the highest radon exposure, and eight studies that examined the effects of radon in the home.

The committee concluded there was a direct dose-related connection between radon and lung cancer. The greater the radon concentration, the report said, the greater the lung cancer risk. Radon was not linked to any other type of cancer.

Based on mathematical models, the committee estimated that radon exposure played a role in 15,400 to 21,800 of the 157,400 lung cancer deaths reported in the United States in 1995. This would mean that radon exposure is second only to cigarette smoking in causing lung cancer.

The committee concluded that 2,100 to 2,900 radon-linked lung cancer deaths occur among nonsmokers each year. This means the vast majority of radon-linked diseases occurs among people who also are at risk of lung cancer from smoking, the committee said.

``Smokers who are exposed to radon appear to be at greater risk for developing lung cancer because the effects of smoking and radon are more powerful when the two factors are combined,'' said Samet.

If radon levels in all American homes were reduced below the EPA-recommended levels, the NRC committee concluded, the number of radon-related lung cancer deaths among nonsmokers would be reduced by about 1,000.

The NRC is a part of the National Academy of Sciences, a private organization chartered by Congress to conduct research at the request of government agencies.

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