Radon Hazard in Oregon

BACKGROUND:  Radon is a naturally occurring radioactive gas formed by the natural breakdown of uranium in rock, soil and water.  Radon gas is colorless, odorless and tasteless, and moves up through the ground into buildings through cracks and other holes in their foundations. Once inside, radon can become trapped and build up to high levels. Radon is the second leading cause of lung cancer in the United States, and the leading cause among non-smokers. The Environmental Protection Agency and the Surgeon General recommend all homes be tested for radon.

METHODS:  We analyzed data from 28,000 short-term and 8,500 long-term radon tests done in Oregon. A rank-sum method was used to determine potential radon hazard by zip code, based on mean test value and the percent of tests exceeding the action level of 4 pCi/L. Maps of address-level data illustrate radon hazard potential at a finer scale than the zip code level.

RESULTS:  Long-term tests showed 29 of 108 (27%) zip codes in the Portland area had high potential for radon hazard, and an additional 42 (39%) had moderate potential for radon hazard. Only 22% of Portland-area zip codes had no tests exceeding the radon action level. There was good agreement between short-term and long-term test results. Most tests were done in the Portland area, but statewide results also show variation in potential radon hazard.

CONCLUSIONS:  Many Oregonians live in areas with high or moderate potential for radon exposure, putting them at increased risk for lung cancer. Even areas with low radon potential have test values indicating mitigation is needed, so all homes should be tested. Radon test data can support state efforts to promote testing and mitigation.