420 ILCS 44/5
The General Assembly declares that it is in the interest of the people of Illinois to establish a comprehensive program for determining the extent to which radon and radon progeny are present in dwellings and other buildings in Illinois at concentrations that pose a potential risk to the occupants and for determining measures that can be taken to reduce and prevent such risk. The General Assembly also finds that public concerns over the dangers from radon and radon progeny may give rise to unscrupulous practices that exploit those concerns but do not mitigate the dangers from radon and radon progeny. It is therefore declared to be the public policy of this State that in order to safeguard the health, property, and public welfare of its citizens, persons engaged in the business of measuring the presence of radon or radon progeny in dwellings and reducing the presence of radon and radon progeny in the indoor atmosphere shall be regulated by the State through licensing requirements.
420 ILCS 44/5