Fukushima Daiichi nuclear disaster on the International Nuclear Event Scale (INES). This scale runs from 0, indicating an abnormal situation with no safety consequences, to 7, indicating an accident causing widespread contamination with serious health and environmental effects. Prior to Fukushima, the Chernobyl disaster was the only level 7 event on record, while the Three Mile Island accident was rated as level 5. A 2012 analysis of the intermediate and long-lived radioactivity released found about 10–20% of that released from the Chernobyl disaster. Approximately 15 PBq of caesium-137 was released, compared with approximately 85 PBq of caesium-137 at Chernobyl, indicating the release of of
Radiation effects from the Fukushima Daiichi nuclear disaster Commission (NSC) of Japan published the results of the recalculation of the total amount of radioactive materials released into the air during the incident at the Fukushima Daiichi Nuclear Power Station. The total amounts released between 11 March and 5 April were revised downwards to 130 PBq for iodine-131 (I-131) and 11 PBq for caesium-137 (Cs-137). Earlier estimations were 150 PBq and 12 PBq. On 20 September the Japanese government and TEPCO announced the installation of new filters at reactors 1, 2 and 3 to reduce the release of radioactive materials into the air. Gases from the reactors would be