Colorado results of the EPA-funded, 16-state, indoor radon-gas survey. Some tabulations are by geologic formation, zip code, county, month tested, and different house constructions. 51 pages, 1 figure, 9 tables. Digital PDF download. OF-91-04D
For this study, the EPA supplied the charcoal canister test devices and had the analyses conducted in the EPA laboratories in Montgomery, Alabama. The EPA also supplied the states with a random listing of names, addresses, and phone numbers of people who could be contacted for participation.
The Colorado Geological Survey, the Colorado State Health Department, and most of Colorado’s sixty-three counties made contact with participants and installed the test devices. Several factors were considered as guidelines for conducting the survey. The placement strategy was to cover the entire state focusing on geologic area and population. As expected, measured values were strongly influenced by the geologic setting. A basic statistical analysis statewide and of each county was conducted. Statewide, 42.96 percent of the 1,911 valid test results exceed EPA’s 4.0 pCi/1 guideline.