As a result of rising Cause_change_of_position_on_a_scale ambient radiation levels off-site , a radius exclusion zone was created Creating 36 hours after the accident .

On April 15 , 2013 , an envelope that preliminarily tested Testing positive for ricin , a highly toxic protein , was intercepted Preventing_or_letting at the US Capitol 's off-site mail facility in Washington , D.C .

All told , some 154,000 residents evacuated Escaping from the communities surrounding the plant due to the rising off-site levels of ambient ionizing radiation caused Causation by airborne radioactive contamination from the damaged reactors .