Radon is a naturally occurring gas that is part of the radioactive decay chain that starts with uranium and ends with lead, and it is found in soil and in some older building materials in the form of radium. Radon enters buildings through the soil under the house, if there are construction faults or leaks in the building's foundation. According to most countries national regulations, the action or reference value of radon in indoor air is 200 Bq/m3. Millag can offer radon isolations, which meet the latest requirements. Millag uses a particular RAC membrane characterized by its resistance to most chemicals.