Radon is a colorless and odorless gas produced by the radioactive decay of uranium.
It has been linked to lung cancer.
Radioactive materials in the soil decay and give off radon gas and the gas gets into a house through crawl spaces, sump pump pits, joints and cracks in basement slabs or sub-floors.
The EPA has set a standard of 4.0 picocuries per liter for radon.
The EPA says you can be exposed to that level indefinitely with no increased risk of lung cancer over that of a non-smoker.
Exposure to 10.0 picocuries per liter for 20 hours per day for 70 years gives you the same risk of lung cancer as smoking a pack of cigarettes a day, again, according to the EPA.
As a result, the EPA recommends that radon mitigation systems be installed if the radon level in the house exceeds 4.0 picocuries per liter.
You can test for radon as part of the home inspection process. A 48-hour test is conducted and you get a report on the radon concentration that was present in the home during the test. The test will cost anywhere from $30 to $175 but expect to pay about $125 to $150 for the most reliable type of testing.
Radon problems can be fixed relatively easily. Costs tend to run from $200 to $1,500 with $800 to $1,000 being average. Depending on market conditions, sellers may be willing to pay the cost of a radon mitigation system if requested as part of the inspection resolution process.
There is quite a bit to know about radon. HERE is a link to the EPA Radon Guide. Review it when you have a chance.