be very cautious about believing what 'public officials' say. They are notorius for undermining the 'truth'.
Ask yourself why the American naval vessel moved to well over 100km away from japan when the explosions happened. Is it because its good for your health? NO! so to say that its normal levels is very concerning. You will not get a brass razoo when you get cancer a few years down the track!
Its called Plausible Deniability. Great for getting big business and government off scott free, while you suffer. Just like fluoride in the water, hey its safe, that's why Hitler used it in the concentration camps!