Aug 20, 2013: Fukushima Governor Yuhei Sato has urged the central government to take the initiative in dealing with the wastewater leak at Fukushima Daiichi [...] The prefecture’s top officials held an emergency meeting on Tuesday following Monday’s revelation of a massive leak of radioactive water from a storage tank. The governor described the situation as a national emergency [...] Senior Fukushima prefectural official Shoji Furuichi [...] asked [Tepco] to quickly find out whether the leak has contaminated the environment. Furuichi called the leak extremely regrettable
August 20, 2013: TEPCO reports worst radioactive leak from tank at Japan’s Fukushima [...] Some 300 tonnes of radioactive water is believed to have leaked from a tank at Japan’s crippled nuclear plant, the worst such leak since the crisis began, the operator said Tuesday. [TEPCO] said the leak was believed to be continuing Tuesday at Fukushima and it had not yet pinpointed the source of it. [...] But the latest leak was the worst from a tank in terms of volume, the TEPCO spokesman said. TEPCO admitted the toxic water might contaminate groundwater and flow into the Pacific Ocean “in the longer term” [...] So far four tonnes of the spilled water had been retrieved since Monday evening [...]

See also: Officials: 'Nuclear Fuel Material' or the like leaked during today's Level 1 event near Unit 4 at Fukushima plant -- "We will explain this incident in the press conference" (MAP)