Water that the Japanese Government is planning to release into the Pacific Ocean from the crippled Fukushima nuclear plant contains radioactive material well above legally permitted levels, according to the plant's operator and documents.
Authorities are running out of space to store contaminated water that has come into contact with fuel that escaped from three nuclear reactors after the plant was destroyed in the earthquake and tsunami that struck north-east Japan in March 2011.
The plan to release just over a million tons of water, currently stored in 900 tanks, into the Pacific has angered local residents and environmental organisations, as well as groups in South Korea and Taiwan fearful that radioactivity might wash up on their shores.
Tokyo Electric Power Co (Tepco), which runs the plant, has until recently claimed that the only significant contaminant in the water is safe levels of tritium, which can be found in small amounts in drinking water, but is dangerous in large amounts.
The Government has promised that all other radioactive material is being reduced to "non-detect" levels by the sophisticated Advanced Liquid Processing System (ALPS) operated by the nuclear arm of Hitachi Ltd.