Scientist: Radon gas levels in New Ulm, Brown County alarmingly high

By RON LARSEN

Journal Staff Writer

NEW ULM--There's a silent stalker in nearly everyone's home in New Ulm and most of Brown County that strikes without warning and is responsible for possibly 10 to 25 deaths throughout the county every year.

It's called radon gas, and it has been found in life-threatening quantities in over 50 homes in New Ulm, according to Dan Steck, physics professor at St. John's University, Collegeville.

Steck heads The Minnesota Radon Project at Schaefer Environmental Radiation Laboratory and is devoted to raising the awareness of Americans to the odorless, tasteless, radioactive gas which is a natural byproduct of disintegrating, or decaying radium.

For whatever geological reasons the greatest concentration of high levels of radon gas occur within the Upper Midwest, Steck said, and Minnesota has more than its share of radon hot spots.

"You live in a high-rate zone," Steck told New Ulm residents last Monday. The good news is the gas can move only a short distance laterally so there's little chance that residences not directly over the gas will ever have a problem.

"Over time, it dies, decays and changes into something else," Steck added. But the amount of time it takes for that to happen is little consolation to those living in a high-rate zone.

So, it becomes a matter of what is a high-rate concentration and how is the concentration level measured.

Gas concentration is measured in units called picoCuries per liter or pCi/L. The U.S. Environmental Protection Agency recommends action be taken to evacuate, or mitigate the gas from a living area if the concentration exceeds 4 pCi/L.

When Steck tested the 56 homes in New Ulm, he found radon concentration averaged 10 pCi/L, two and a half times the EPA's action level. It's also three times the state's average for homes, and over eight times the national home average.

Not all of Brown County is in the red danger zone of 4-plus pC1/L, however. The "red" zone extends west to about County Road 8 and south to about U.S. Highway 14 where it angles to the Watonwan County border near Godahl. The other red zone in the county is the western end with the line running on a diagonal from the northwest corner west of Springfield to near Comfrey.

The remaining portion of the county is in the "yellow" zone which means concentrations fall between 3 and 4 pCi/L.

"Radon gas is everywhere, but it's only in a few areas, like the Upper Midwest, that it's at a high level," Steck said. "Along the Pacific Coast, the East Coast, South-Central into Texas and the Southeast, levels are at less than one pCi/L."

On average Minnesota's concentrations in homes, in the work place and outdoors ranks well above national levels. In homes, the national average is 1.2, Minnesota's is 3.0. In the work place, the U.S. average is 0.9, and the state average is 1.5. Outdoor readings average 0.4 nationwide and 0.6 in Minnesota.

That the gas can be deadly over a period of years has been established, Steck said. "It's estimated that nationwide about 20,000 people a year die of lung cancer brought on by radon gas, and in Brown County, it's estimated anywhere from 10 to 25 people a year die as a result of exposure to radon gas."

The connection with radon gas is made through "epidemiologic studies of groups of exposed individuals, animal studies and laboratory studies of the effects of radiation," Steck explained.

As there is no difference in the types and behavior of lung cancer induced by radon and other causes, however, Steck said research is being proposed to find a molecular marker in genes to identify the source. That research has not been funded as yet.

What has been proven, Steck said, is that the death rate from radon-induced lung cancer for smokers is much higher than for non-smokers, particularly those who have never smoked.

"Radon and smoking work together," Steck said. "Your radon cancer risk is 10 times that of a person who has never smoked."

Studies have shown a death rate of 71 per 1,000 smokers exposed to 10 pCi/L, Steck said, compared with four per 1,000 non-smokers exposed to 10 pCi/L.

Detection then is the key to living safely with radon gas, but there is no detector that is completely foolproof because the gas can permeate about every known material, Steck said.

The most commonly used detectors are the alpha track and the charcoal canisters, according to Steck. The alpha track detectors are used for long-term testing while the activated charcoal canisters can be used only for short periods.

"These detectors are meant to be used only in the two- to seven-day tests," Steck explained. "Radon gas is adsorbed by the charcoal, but so is water and other things like tobacco smoke. If the packet has been opened to expose the canister, then the results may be in error."

Steck said that testing of the charcoal canister detectors showed a 50 percent failure rate.

"The data show that these tests fail too often to give a useful number in a high radon state like Minnesota," Steck continued. "The EPA allows these tests because they concluded most people wouldn't take a 90-day test. They felt any test, even one that fails half the time is better than no test."

The core material in the alpha track detector is much less apt to pick up elements that would contaminate the test, Steck said. In fact, he said crumbled-up plastic lens used in eye glasses are what he uses in making his own alpha track detectors.

"The amount of time a detector sits on a hardware store shelf is an important consideration," Steck added. "If it has sat there too long before being used, you may find out more about what's happening at the store than what is going on in your home."

Whichever type of detector you buy, however, will need to be sent away to have the reading made and the results returned to you.

If you elect to go with the short-term charcoal canister detector, Steck said the house must be kept completely closed during the test period, and the detector should be placed in the lowest "lived-in" level. It should not be moved during the test.

For long-term testing, 90 days or more, with the alpha track detector, "the house can be operated normally, and the detector can be placed anywhere that people spend significant blocks of time. If only one is used, I recommend measuring the level closest to the ground where people spend more than 10 hours per week. To get a reading that better represents true exposure, they could move the detector from floor to floor for time periods that reflect the proportion of time spent on that floor."

Steck favors testing over a longer period because "radon levels can very from room-to-room, day-to-day, month-to-month, but those results will be pretty consistent from year to year." He suggests doing a test through part of the heating season and into the non-heating season.

Steck said, in monitoring radon gas, homeowners who have forced air heating systems should keep in mind that the system can circulate the radon gas throughout the house.

Fortunately, there is a relatively simple, and relatively inexpensive way to rid your home of the radon gas threat. The solution is to vent the radon gas coming up through the ground into the atmosphere, Steck explained.

"Most homes are easily mitigated with a suction system. Mitigators normally will drill a 3-6 inch hole in the basement floor near the lowest point, put in a straight pipe with a fan in the attic and vent the system through the roof," Steck said. "The fan sucks the radon gas through the pipe, out into the atmosphere. If the pipe goes out the side of the house, the radon gas can re-enter the house."

If you're installing a suction system while building the house, Steck recommends a layer of gravel covered with a impermeable plastic sheet underneath the concrete slab for the basement. The mitigator cuts a hole in the plastic for the pipe, and the plastic cover allows the system to "pull" gas from under the entire house.

"The gravel layer allows the suction system to pull radon gas from under all of the house," Steck said. "You'll see mitigators use smoke around the house's foundation to test the system; if the smoke rises in the pipe, they know it's working properly."

A typical new installation suction system can run anywhere from $500-$3,000, Steck found in a survey of contractors. But some advance planning, particularly during new construction like having a 3-6 inch "exhaust" pipe installed during construction, can save the homeowner money.

"Too many people waste money on detectors that don't give them good information about their radon risk," Steck concluded, "and some people waste a great deal of money on a mitigation system that they may not need."