Bob and Jeanne Mehlberg knew little about the radioactive gas called radon until they tried to sell their home, a three-bedroom split-level in a far western suburb of Chicago.
Included among the routine riders in their contract–the typical inspection, the usual requests that appliances get left behind–was an odd demand: The buyer wanted a radon test. To the Mehlbergs` astonishment, the test picked up excess radon in their basement. And the buyer, a New York lawyer, insisted they make repairs.
”I was unaware of the hazard,” says Mehlberg, an engineer who fixed the basement himself, ”or I would have done this five years ago.”
Radon is a naturally occurring gas. It drifts out of radium and uranium traces in the ground and dissipates harmlessly into the air. Sometimes, however, it drifts from the ground into the basements of houses, where it can seep into living areas and get bottled up.
Indoors, those high concentrations can get dangerous: Breathing high levels of radon over a lifetime could cause from 5,000 to 20,000 lung cancer deaths a year, according to the Environmental Protection Agency.
Five to 15 percent of all houses, the EPA estimates, may have a radon problem. In Illinois, studies by the Department of Nuclear Safety found excess radon in about 10 percent of homes.
Radon tests soon will become commonplace when houses are bought and sold, some real estate agents predict. Richard Toohey, a radon researcher at the Argonne National Laboratory, sees a day when banks will refuse to offer mortgages for untested homes. Homeowners could sue builders; at least one radon suit against a builder already has been filed in Pennsylvania.
But despite the sudden concern, some skeptics say the whole radon crisis is overblown.
For example, when retired physicist Harold May tested his Hinsdale home, he found about 10 times more radon than the Mehlbergs did. The Mays` basement family room is contaminated with enough radon, the EPA estimates, to do the damage of 20,000 chest X-rays a year.
But May, who studied radon for 30 years at Argonne National Laboratory, believes that it takes more radon than that to constitute a risk.
”I don`t think there`s any real hazard,” he says. ”And I have a hard time believing there are any homes in the Chicago area that really present a hazard.”
Indeed, a number of researchers disagree with the EPA`s standards. EPA scientists can prove only that massive, long-term doses of radon, such as those found in uranium mines, can cause lung cancer. They don`t know if the much smaller amounts found in houses can do any damage at all. And some researchers, studying radon at Argonne and Northwestern University, believe it can`t.
But to be safe, the EPA assumes that all radon carries some risk.
How much of the radioactive gas seeps into a house and collects into potentially dangerous concentrations depends on seven factors, all working together:
— What`s underground? A large, shallow mass of uranium-rich rock, like the Reading Prong that stretches under parts of Pennsylvania, northern New Jersey and southern New York State, can be extremely dangerous because of the radon it emits. About half the houses in Pennsylvania appear to have excess radon. A few have radon readings that make Harold May`s air look like pure oxygen.
On this account, Illinois is safe: It has no radioactive masses comparable to the Reading Prong, says Robert H. Gilkeson, a geologist with the Illinois Geological Survey.
Researchers are, however, investigating a small mass called Hick`s Dome that lies under sparsely populated Hardin County in southeastern Illinois, says Bruce Rodman, the spokesman for the Department of Nuclear Safety. About 200 radon monitors have been placed in homes in the southernmost seven counties.
— How permeable is the soil? A heavy, impermeable clay can block even large amounts of radon, but sandy or gravelly soil is like an open door to migrating gas.
It is hard to qualify the soil across an entire state. Researchers at Argonne National Laboratory say they find elevated radon readings in the homes of some employees who live in the western suburbs along Ill. Hwy. 53, including Glen Ellyn, Naperville and Arlington Heights, in an area of gravel and sand deposits.
Most Chicago homes, on the other hand, are built on heavy clay and could prove to be more radon-resistant. Clay can be a formidable barrier; it is one reason that houses in Georgia have so little radon. ”Twelve inches of that good old Georgia clay will stop radon like a sheet of steel,” says B.V. Alvarez, president of Air Chek, a company that makes radon testers.
Even the shrubbery around a house may increase or decrease the radon inside. Either the roots could steal radon from the soil and release it harmlessly through the leaves, says Barbara-Ann Lewis, a researcher at Northwestern University, or they could dig air spaces in the soil, thus helping move radon to the basement wall.
— How solid are the basement floor and walls? If the floor is cracked, the sump hole unsealed or the floor of a crawl space unpaved, radon molecules can nose their way indoors.
Usually, these entry points are easy to barricade. It cost Bob Mehlberg $150 in materials, for example, to seal his sump hole and ventilate it so the radon-contaminated air was forced back outdoors.
Basement radon usually is not dangerous unless the level is high, the basement gets used frequently or the radon seeps upstairs into the living areas, Rodman says.
— Are the building materials radon-rich? Brick, concrete and stone can all emit radon because they are derived from the earth. They may have to be covered with a sealant if indoor radon levels are high.
— Is the air pressure lower indoors than out? If appliances draw air in from the basement and vent it to the outdoors, the house may pull radon-laden air in from the soil to compensate.
— Is the local water supply extremely high in radon? When water splashes out of the faucets and shower, it can release radon into the air. But according to Larry Jensen, head of the EPA`s radon program for the Midwest,
”Lake Michigan and (Illinois) rivers have not shown much in the way of radon. By far, the greatest source of radon will be the soil.”
— How well-ventilated is the house? Open windows and good ventilation sometimes can dispel a radon problem before it begins. But if radon collects in an energy-tight or winterized house, it may not be able to escape.
In fact, the recent push to make houses air-tight for energy savings may have worsened a pre-existing radon problem, some researchers say. ”Reducing the ventilation rate by half would just about double the radon level,” writes Ellen J. Greenfield in her new book, ”House Dangerous” (Vintage Books, $7.95).
But Sam Taylor, a physicist with Terradex, a radon testing-device manufacturer in Glenwood, warns: ”The point about radon is that there are so many factors that affect it. It`s hard to pin down high-risk areas, or even neighborhoods. You almost have to come in and measure every house.”
That is exactly what the EPA wants homeowners to do.
Early this year , starting with 10 states, the EPA`s nationwide radon survey will get underway. Meanwhile, many states are running surveys of their own; in Illinois, results from all 102 counties should be in by July 1.
So far, the Illinois Department of Nuclear Safety has tested basements and living areas of houses across Illinois. Counting basements, about 25 percent of the houses had excess radon. Counting living areas only–even those below ground level–just 10 percent of the homes were over the EPA`s ”action level.”
To many people, the radon crisis sounds sudden; that`s because it is. Radon has drifted up from the ground since the dawn of time, but the scare only started in January, 1984.
That month, Stanley Watras, a construction engineer, moved his family into a new brick-and-wood home in the countryside of Pennsylvania. He also began setting off the radiation alarms at the Limerick nuclear power plant, where he worked.
Some days Watras would breeze in for 15 minutes, turn around to leave, pass through the radiation monitors and find he was loaded with radiation. Day after day, the alarms went off when Watras tried to go home. Finally, in the winter of 1984, he persuaded Philadelphia Electric Co., operator of the plant, to bring a Geiger counter to his new house.
The counter went beserk.
Stanley Watras` new house had been built smack on uranium-rich bedrock, on the southern tip of the Reading Prong. About half a million houses sit on the Reading Prong, but few, a state survey showed, run as high as the Watras home.
It was a worst-case example, a homeowner`s nightmare. The house was so radioactive it almost crackled. One year within those walls, state officials said, was like getting 455,000 X-rays–or, according to some calculations, the same as smoking 135 packs of cigarettes a day.
