Japan's nuclear safety agency has more than doubled its estimate of the amount of radiation released into the atmosphere from the crippled Fukushima nuclear plant.
The Nuclear and Industrial Safety Agency says it believes the earthquake-stricken Fukushima plant emitted nearly 800,000 terabecquerels of radioactive material into the air in the days after it was hit by a massive tsunami.
That is more than double the original estimate and is based on new information suggesting the No.1 and No.2 reactors suffered meltdowns much earlier than thought.
The revision reveals the failure to contain the disaster resulted in much more radioactive contamination of the soil, sea and air than the plant's operators had acknowledged.
The disaster is rated a maximum seven on the international nuclear accident scale, the same level as the Chernobyl meltdown 25 years ago.