Iowa City makes testing for cancer-causing gas a requirement in rental units

Editor's note: A previous version of this article said radon gas in Iowa does not come from uranium but from radium. However, when uranium 238 undergoes radioactive decay it later becomes radium 226. The radium then decays into radon. 

Radon, a natural radioactive gas found in some structures, is the leading cause of lung cancer in non-smokers in the United States. 

It is responsible for about 21,000 deaths nationwide and about 400 deaths in Iowa every year, according to the Environmental Protection Agency. 

To curb the impact of radon locally, the city of Iowa City will require property owners and managers of single-family detached and duplex rental properties to verify units have been tested for elevated radon levels. The city estimates there are about 3,600 units across town. 

In Iowa City, it's possible one-third of rental units will have elevated levels and need mitigation systems, estimates Dr. Bill Field, a professor with the University of Iowa Department of Occupational and Environmental Health. 

The Environmental Protection Agency says if a home has radon levels of 4 picocuries per liter (pCi/L) of air or higher, which are considered elevated, it should have a mitigation system installed. Iowa's average indoor radon level is 8.5 pCi/L of air while the average nationwide is 1.3 pCi/L of air. 

Anywhere between 50% to 70% of homes across Iowa have elevated radon levels, according to the Iowa Department of Public Health. 

Field said radon gas in Iowa’s soil comes from the state's long history of glacial movements. Radon developed from the pulverizing of granite rock by the movement of glaciers across the region. The pulverization process left deposits of finely ground rocks that contain radium. The decay of radium emits radon gas, which is odorless and tasteless.

The gas seeps out of the soil and enters structures through cracks in the foundation and openings around pipes and drains. Long-term exposure to radiation from radon can lead to cellular damage which can cause cancer in the lungs. 

Field said there's no threshold or minimum time for how many months or years of exposure to radon are enough to cause lung cancer. 

"But the longer you're exposed to radon, the more likely you'll get it," he said, adding there are many factors, including genetics and smoking that impact the likelihood of developing cancer.

Starting July 1, city officials will start working with property owners and managers to ensure units are tested, according to the release. A state-licensed, third-party inspector is required to conduct the testing. 

It will take about two years to check all the properties. 

The release says that if a rental unit has a level of 4 pCi/L or higher, it will be required to have a mitigation system installed. The system will have to be installed by a radon mitigation specialist certified by the state of Iowa. 

The majority of rental units will be required to retest for hazardous radon levels every eight years while units with basement bedrooms will be required to test every four years. 

Owner-occupied properties are encouraged to test for radon but it's not required by the Iowa Housing Code, according to the release.

The city will require all single-family detached and duplex units that become rentals after July 1 to comply with the regulation as testing for radon is part of the rental inspection process.

Concerns regarding radon were voiced as early as 2005 when the U.S. Surgeon General issued a national health advisory. 

Reach Hillary Ojeda at 319-339-7345, hojeda@press-citizen.com or follow her on Twitter at @hillarymojeda