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Silent Killer: The Risk of Radon in Siouxland Homes

SIOUX CITY | A silent killer was in Frank and Diane Gruber's Morningside home.

They didn't know it until the house was tested for radon -- a colorless, odorless gas produced by the decay of uranium. It occurs naturally in soils, rock and water.

When radon enters buildings through foundation or basement cracks, it becomes trapped and accumulates in the lowest level, usually basements. Breathing in the radioactive gas at high levels over a long period can cause lung cancer.

The radon concentration in the Grubers' home was as high as 16 pCi/L, or picocuries per liter -- four times the level at which the Environmental Protection Agency recommends corrective action be taken. After testing with a digital radon detector, the Grubers installed a radon mitigation system, which removes the gas.

More Siouxland homeowners are testing for radon, said Michelle Clausen Rosendahl, director of Environmental Services for the Siouxland District Health Department.

The agency for seven years has offered short-term radon test kits at its 1014 Nebraska St. office. Interest increased after officials worked with Sioux City hospitals and the June E. Nylen Cancer Center on a public outreach campaign earlier this year.

"We've seen demand for our test kits go up probably five times than what they normally are during the year," she said. "If radon was something that made people sick acutely or immediately they would be more aware of it."


The EPA estimates 6-8 million U.S. homes have elevated radon levels. The Iowa Department of Public Health reports that as many as five in seven Iowa homes have radon levels above 4 pCi/L.

“We could be sitting here and the level could be 2 or 5,200 and we wouldn’t know the difference,” said David Canny, co-owner of Radon Mitigators Inc., of Sioux City.

Canny installs radon mitigation systems in about 100 Siouxland homes each year.

"We're pretty equally distributed across town," said Canny, who lives on Sioux City's north side. "If you look at our neighborhood, you can throw a stone within three, four blocks, and there's at least a dozen homes that have put systems in."

Canny said elevated radon levels are common in properties close to water tables. Properties near Perry Creek have tested between 30 and 40 pCi/L. Elevated levels also have been recorded in Riverside along the Big Sioux River and in Sergeant Bluff.

“In Dakota Dunes you don’t see as high of numbers, but the percentage of homes tends to be higher,” Canny said. “You tend to see more like 6 to 8 because it’s that loose sandy soil, but you do see a lot of homes that are above 4 (pCi/L).”

The EPA first became aware of the extent of the radon problem in the United States in 1984, when radiation detectors detected radioactivity on a Pennsylvania nuclear plant worker's clothing. The radon decay products found on the man's clothes were later traced to his home.

The discovery prompted the EPA to conduct short-term radon testing in homes and basements in 42 states over four years.

Pennsylvania's radon levels were among the highest in the nation as expected, but at 60 percent, the state did not have the greatest percentage of homes with elevated radon levels. Iowa led the way with 72 percent, followed by North Dakota at 63 percent and Nebraska at 54 percent.

"The levels we found in Nebraska and in Iowa are not as high as those out in Pennsylvania, but the number of homes is much higher," said EPA Region 7 Radiation and Indoor Air Specialist Bob Dye.

Radon screening tests conducted by the Iowa Department of Public Health from 1990 to 2011 show radon gas levels equal to or above 100 pCi/L in areas of numerous counties around the state, including Woodbury County.

Dye said geologists believe Iowa's high radon concentration is due to the movement of the glaciers through the state.

"I've asked a number of people why Iowa would be so high, and geologists have told me that back many years ago when the glaciers were here, the glaciers would kind of go out of the southern part of Iowa and go back up," he said.

Dye said these glacier shifts ground the soil very fine, allowing radon gas to move more freely.

After conducting radon testing in the mid to late 1980s, Dye said, the EPA developed a statistically valid map at the state level from the test results and then partnered with the U.S. Geological Survey to create a radon potential map.

The map, which designates every county in the nation as being in zones 1, 2 or 3, is based on radon testing, the identification of uranium deposits from Department of Energy flyovers and foundation types, according to Dye.

All of Iowa's 99 counties fall in Zone 1, the highest potential for having an average indoor radon screening level greater than the EPA's recommended action level.

"No matter what zone you're in, the EPA and the surgeon general recommends that every home test for radon," Dye said. "It doesn't matter what your neighbors have. You have to test your home."


The Grubers received a radon brochure when they purchased their Morningside home in 2001, but the couple decided to forgo radon testing.

"We said, 'No. It's nothing of importance or anything,'" Frank Gruber said. "We were pretty ignorant about it."

A couple of years later, the Grubers built an addition. During the remodeling process, they lived in the basement. That's when Gruber said they decided to test their home for radon with a short-term test kit.

The result of the first test was 16.2 pCi/L. Subsequent tests in the following months revealed radon levels at 8.8 and 6.9 pCi/L.

Gruber then purchased a reusable digital radon detector from eBay for $100. He said he tested rooms upstairs and downstairs and found levels consistently between 7 and 8 pCi/L.

The test results themselves were not enough to convince the Grubers to act. When their Pomeranian developed nasal cancer and had to be put down, Gruber said, they contacted Radon Mitigators Inc.

The Grubers adopted the dog from a smoker when it was 6 years old. Although it can't be proved that a radon mitigation system would have helped extend the dog's life, Gruber said he still wonders.

"That's what really told us, 'We have to get something done,'" he said. "We still believe that our dog would've survived a lot longer if we had done it earlier."

After the mitigation system was installed in his home in 2006, Gruber said radon became almost nonexistent.

"It barely registers 1 pCi/L. Sometimes zero," he said.


Canny said most people find out about the dangers of radon during a housing transaction.

Iowa law does not require that homes be tested for radon before sale. Real estate agents must provide buyers with an "Iowa Radon Home-Buyers and Sellers Fact Sheet."

According to Canny, it is up to the buyer to request that an inspector test the home for radon. Radon testing is not included in a regular home inspection and costs an additional fee.

If a property tests high for radon and the buyer backs out of the deal, Canny said, the seller must disclose the results to future buyers.

"Once the house is tested for radon and the number is determined to be high, then the next time around, the seller would have to disclose that to the next prospective buyer," he said.

Canny said some property owners with radon levels between 4 and 6 pCi/L have successfully lowered their levels by sealing cracks and closing up sump pit barrels. An active mitigation system, he said, is the only way to reduce radon in homes testing above 6 pCi/L.

A typical active radon mitigation system consists of a 4-inch PVC pipe that extends from a hole in the basement floor through the roof. A fan sucks the radon gas from below the slab up the pipe and vents it outside.

“As the radon comes up from the soil, it gets pulled into these sealed pipes and then up and out the roof,” Canny said.

The average price is $1,100-$1,400. Canny said the cost is more for a very large home or a home with a crawl space.

“In some cases, where we’ve done commercial properties, schools, day care centers, we’ve had to go through and put in multiple systems just to cover the area,” he said.

There is no way to test the soil before a new home is built to determine whether it will have elevated radon levels. Canny said about half of the home builders in Sioux City are automatically installing passive mitigation systems in new homes.

Canny said builders place drain tile in a central pit and then cover it with a layer of pea gravel and a layer of plastic. A PVC pipe runs from the central pit up to the roof to vent the radon. The cost of a passive system is half the cost of an active one.

Gruber said he is pleased with his active mitigation system, which he said blends in with the rest of the plumbing.

"We worked together to find a place where the pipe would go so you wouldn't be able to see it much except in the unfinished areas," he said. "They were very considerate to vent it out through the garage and up. Nobody's really noticed it."

Read more here: http://siouxcityjournal.com/news/local/a1/silent-killer-the-risk-of-radon-in-siouxland-homes/article_e6a00d72-1619-520c-a08c-be94f4f31327.html