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About Radon Levels in Lewis and Clark County

The average national indoor radon level is 1.3 pCi/L. (FAQ: What is a picocurie?)

The average indoor radon levels of Lewis and Clark County, as determined by radon test results from Air Chek, is 7.9 pCi/L

Local News

Radon Risk Chart for Lewis and Clark County


    Results under 2 pCi/L

    Results between 2 and 3.9 pCi/L

    Results 4 pCi/L and above


Check Your Own Radon Levels!


Additional information about radon levels in Lewis and Clark County may be available through this website.


State Radon Officer

Michael L Gustafson
(800) 546-0483
(406) 444-6592
DEQ Headquarters
1520 E 6th Avenue
Helena MT, 59601