More than just dirt The kind of soils your land has will greatly affect what you can build and grow on it.
Soils can vary widely, even over a distance or just a few feet.
Whether you live on the eastern plains or the Western Slope, you need to work with the geology and soils of the land - not against them. If readings are high, install proper ventilation. Is your building site on or near an abandoned coal mine, a geotechnical engineer should conduct a subsidence investigation. If you are building in a historic metal mining district, you should have an environmental audit done to evaluate mine waste material on your site and the extent of underground mine workings. Information on specific problems is also available from the Colorado Geological Survey, the Colorado Division of Minerals and Geology and the Environmental Protection Agency.