In some types of terrain, radon testing can require special consideration. One such case is in areas of karst geology. Karst is a broad term used by geologists for features where portions of rock have been dissolved away by water.
Although karst is found in many areas of the United States, Alabama, particularly north Alabama, has many of these geologic formations. Radon levels can be extremely variable in these areas. Therefore, in order to provide the correct testing guidance, one must determine whether they live in an area affected by this geologic condition.