No, actually your data validates him. Maybe you are confusing 'm' with 'μ', that is, milli- (10^-3) with micro- (10^-6)? >The estimated occupational effective

No, actually your data validates him. Maybe you are confusing 'm' with 'μ', that is, milli- (10^-3) with micro- (10^-6)? >The estimated occupational effective dose for the aircraft crew (A 320) working 500 h per year was 1.64 mSv. 1.64 mSv (milliSieverts) / 500 hours = 3.28 μSv/hour. A 3-hour flight is 10 μSv. For comparison, the FDA letter [1] linked in another comment here cites the effective dose of the backscatter x-rays as 0.25 μSv. The cosmic ray dose from a 3 hour flight is 40 times that of the backscatter x-ray. Pretty much "dwarfs it". (Note that while the FDA letter says the effective dose is 0.25 μSv, the footnote there (11) says that RapiScan is <=0.05 μSv. Not sure how to parse this -- maybe the 0.25 μSv is a regulatory definition, not the real dose. An NPR article [2] I cited earlier claimed 0.02 μSv, consistent with that <=0.05 μSv figure. While I'm in these parentheses, NOAA has a table [3] of cosmic ray doses as a function of altitude. Pretty much consistent with your source -- 3 μSv/hr at 30,000 ft, 6 μSv/hr at 40,000 ft). [1] http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/SecuritySystems/ucm231857.htm http://www.fda.gov/Radiation-EmittingProducts/RadiationEmitt... [2] http://www.npr.org/templates/story/story.php?storyId=126833083 http://www.npr.org/templates/story/story.php?storyId=1268330... [3] http://www.swpc.noaa.gov/info/RadHaz.html http://www.swpc.noaa.gov/info/RadHaz.html