Maryland is the smallest state in terms of size and yet it is one of most populous in the entire US. The state does not have an active radon program.
EPA Radon Levels
Maryland has 20 counties and 8 (40%) have been assigned Zone 1 counties by the EPA. Zone 1 counties have the highest potential to have homes test higher than 4 pCi/L. Maryland's state radon zone average is 1.9, which is the average of all county zone ratings the EPA has assigned the state, ranking it 29 among all states.
The radon levels in Maryland are above average. Some Maryland homes have been found to have radon levels higher than 200 pCi/L. These levels are 50 times higher than the action guidelines set by the US EPA. If you were to spend your lifetime in a house with radon levels of just 10 pCi/l - a fraction of the levels above - you have a lung cancer risk similar to smoking nearly a pack of cigarettes a day. As such, there’s an increased risk for all homeowners, which is why we recommend testing exposure levels at least twice a year.