The ICRP has published it's long awaited new dose levels for radon. These new dose levels will in my opinion should lower the acceptable levels of radon in a workplace significantly.

I do not know what the USA uses as it's teranorm dose restrictions are, but the math to get from Bq/m3 to dose in mSv is one of two choices from table 12-7 or the method recommended in the annex A-8 and A-9 is:
6.7 X 10⁻6 mSv per Bq h m⁻3 assuming an equilibrium factor, F, of 0.4. With an occupancy of 2000 h y⁻1 for a worker (ICRP, 1993, 2010)

i.e. 150 Bq/mᵌ X (6.7 X .000001 mSv per Bq h m⁻ᵌ) X 2000 hours = 2.1 mSv dose

In Canada our restrictions to NORM in a workplace safety is typically:
below 1mSv dose, is OK.
1 - 5 mSv dose, employer must begin a radiation safety plan designed to lower dose below 1mSv and track worker exposure (not dosimeter)
5-20 mSv dose, employer must track worker exposure with licenced dosimeter, radiation safety plan to lower dose with a goal of below 1 mSv

Come to CARST in Ottawa April 22-24 to learn more about this exciting change in workplace safety from radon and what changes this might mean for residential levels in the near future!