On 24 May 2012, more than a year after the disaster, TEPCO released their estimate of radiation releases due to the Fukushima Daiichi Nuclear Disaster. An estimated 538,100 terabecquerels (TBq) of iodine-131, caesium-134 and caesium-137 was released. 520,000 TBq was released into the atmosphere between 12 to 31 March 2011 and 18,100 TBq into the ocean from 26 March to 30 September 2011. A total of 511,000 TBq of iodine-131 was released into both the atmosphere and the ocean, 13,500 TBq of caesium-134 and 13,600 TBq of caesium-137. In May 2012, TEPCO reported that at least 900 PBq had been released “into the atmosphere in March last year  alone up from previous estimates of 360-370 PBq total.
In a leaked TEPCO report dated June 2011, it was revealed that plutonium-238, −239, −240, and −241 were released “to the air” from the site during the first 100 hours after the earthquake, the total amount of plutonium said to be 120 billion becquerels (120 GBq) — perhaps as much as 50 grams. The same paper mentioned a release of 7.6 trillion becquerels of neptunium-239 – about 1 milligram. As neptunium-239 decays, it becomes plutonium-239. TEPCO made this report for a press conference on 6 June, but according to Mochizuki of the Fukushima Diary website, the media knew and “kept concealing the risk for 7 months and kept people exposed”.