UPDATE, Noon, Wednesday, The Austrian Central Institute for Meteorology and Geodynamics (ZAMG), which is advising the International Atomic Energy Agency, reports that releases of radioactive Cesium (hazardous life: 300-600 years) from Fukushima now are 20-60% those of Chernobyl; releases of Iodine-131 are at 20% Chernobyl releases.
Update