Fukushima radiation levels

1) Fukushima Update

2) radiation risks -Wikipedia

3) Low Levels of Radioactive Material Begin to Be Detected Across Pacific -Wall Street Journal

Source 1 claims that a radiation level of 21.4 uSv/h (microSieverts per hour) was detected on 17 March 2011 at Fukushima City, 60km (~38 miles) west of the Fukushima Daiichi plant.

Source 2 claims that 100 mSv/yr (milliSieverts per year) are the "lowest clearly carcinogenic level".

Source 3 claims, "As a rule, doubling the distance from the source cuts exposure by a factor of four, says the U.S. Environmental Protection Agency."

Conclusions:

1. 100mSv/year = ~11uSv/hour, which, accumulated over a year, represent a dosage at a "clearly carcinogenic level".
2. The 21.4uSv/h level reported at Fukushima City, 38 miles west of the nuclear accident, is approximately twice the "lowest clearly carcinogenic level". Note that this assumes a constant dosage at this level for an entire year.