Nearly one of every five houses in Maryland has elevated levels of radon, but only about one in 10 homeowners has even checked for the radioactive, cancer-causing gas, new surveys show.
Nineteen percent of 1,126 houses measured across the state were found to have radon concentrations greater than the action level set by the U.S. Environmental Protection Agency, according to a survey conducted over the past year by the EPA and the Maryland Department of the Environment.
"That's high, and that warrants some action," said Dr. Thomas J. Godar, a former president and adviser of the American Lung Association.
The survey -- the first random check of homes in the state -- "just confirmed what we believed all along," said John Goheen, an MDE spokesman. "Radon is a significant problem in Maryland, and we have to take it seriously."
Based on the survey, EPA and state officials estimate that as many as 144,600 homes in Maryland may have elevated radon screening levels, which should prompt more extensive testing.
Radon is a colorless, odorless gas produced from the decay of uranium, a radioactive mineral found in most soils. It seeps into homes and buildings and can reach dangerous levels in poorly ventilated areas.
Long-term exposure to radon gas can increase a person's chances of getting cancer, most experts say, although recent studies have scaled back estimates of the risk.
The EPA, which at one time blamed as many as 20,000 cancer deaths a year on radon, is now adjusting its risk estimates downward, according to Margo Oge, the agency's director of radiation programs. Based on a recent study by the National Academy of Sciences, the federal government now estimates that the gas may be responsible for about 13,000 extra cancer deaths a year, Oge said.
Despite that, Oge said, "the agency still believes that radon is the No. 1 environmental pollutant that threatens public health. More people are affected from radon than anything else, and we have more certainty of our numbers."
Radon is second only to cigarette smoking as a cause of lung cancer, say EPA officials and most scientists. Lung cancer, which kills about 140,000 people a year, is the nation's leading cancer killer, and smoking is blamed for about 85 percent of those deaths. Maryland has the highest cancer death rate in the nation and one of the highest lung cancer rates as well.
MDE has collected radon readings from more than 60,000 homes since the mid-1980s, and many of them were elevated. The highest short-term measurement, sampled over a few days, was 895 picoCuries per liter, taken in a home several years ago in Howard County. That is more than 200 times EPA's action level of 4 picoCuries per liter, at which people are urged to do further testing. A picoCurie per liter (pCi/l) is a measure of radon gas concentration.
Those earlier household measurements were not considered representative of the state, however, because they were not chosen for testing at random.
For this survey, MDE staff telephoned homeowners across the state whose names were chosen randomly by EPA, Goheen said. Test kits were mailed to homeowners, who were instructed to place them in their basements or the lowest part of the house for a few days, then mail them back for analysis.
Only about one out of every five or six people contacted was willing to test his or her home for radon, even though the state offered the test kits and results for free.
"Unfortunately, that reflects people's lack of interest," Goheen said. "People just aren't taking this seriously."
Statewide, the average short-term radon level is 3.1 picoCuries per liter, the survey shows. But average readings in five counties -- Calvert, Carroll, Frederick, Howard and Washington -- exceed the EPA action level.
And the survey found at least one home with elevated radon levels in every county in the state, except on the Eastern Shore. The highest was 140 picoCuries per liter in Carroll County.
While most of the highest readings came from Central and Western Maryland, widely known as the state's "radon belt," some also came from areas not usually associated with radon, such as Baltimore City (64 pCi/l) and Calvert (38 pCi/l) and Charles (32pCi/l) counties.
Meanwhile, another survey, conducted for the American Lung Association, finds that 11 percent of those polled said they already have tested their homes for radon. That is about twice the 5 percent estimate given by officials for the past several years.
"It appears that [homeowners] are beginning to respond," said Dr. Godar, who is director of the pulmonary disease section of St. Francis Hospital and Medical Center in Hartford, Conn., and an associate medical school professor at Yale University. He noted that 17 percent of those polled in the Northeast said they already had tested, and about one-third of those surveyed nationwide said they are likely to check their homes in the next year.
But in Maryland and the rest of the Southeast, only about 9 percent said they had tested for radon so far.
VTC "My own theory is that the public may have suffered from circuit overload," Godar said. Compared with such immediate problems recession, crime in streets, drugs and war, he said, "they're not prepared to deal with a long-term, low-level risk."
The survey also found that myths and misunderstandings about radon may be deterring many from testing their homes.
For example, 31 percent of those surveyed believe that radon is not a problem in their region, and 21 percent think it occurs only near chemical or nuclear plants.
try. Tests are relatively inexpensive, often less than $25; and a variety of methods have been shown to safely vent radon gas from homes.
For more information on how to test for radon and fix a problem your home, call MDE's radon hot line, 800-872-3666.