TEPCO says it measured radiation of 2,200 millisieverts at the plant . The reading came from near a tank holding contaminated water . Radiation levels are still high in some areas and have been for several days, but they appear to be decreasing as more people return home after being evacuated. Those levels are strong enough to kill an unprotected person within hours .
TEPCO says it measured radiation of 2,200 millisieverts at the plant . The reading came from near a tank holding contaminated water . The previous highest reading around that tank was 1,800 millisieverts on Saturday . Those levels are strong enough to kill an unprotected person within hours .