Ran across this and not sure whether all our Colorado members know about it:
Both of the PDF files linked on https://www.nachi.org/coloradoradon.htm miss the fact that Radon is the Number two main cause of Lung Cancer behind Smoking which is Number one.
Tilley Home Inspection
These PDFs were generated by the State of Colorado. The CDPHE booklet mentions the smoking comparison on the bottom of page 4.