The operator of Japan's tsunami-wrecked Fukushima nuclear plant is apologizing for yet another leak of radioactive water.
The Tokyo Electric Power Company said on Thursday that about 430 liters of toxic waste water spilled, probably into the Pacific Ocean, when workers overfilled a storage tank.
The company says it was under pressure to fill the tank as high as possible in order to deal with large amounts of rainwater from recent typhoons. The tank did not have a gauge and was built on uneven ground.
The tank is one of about a thousand hastily built structures meant to hold the toxic water used to cool the plant's reactors after they were damaged by the 2011 earthquake and tsunami.
In August, TEPCO said about 300 tons of radioactive water leaked from one of the tanks, most of it reaching the ocean. It also acknowledged that hundreds of tons of toxic groundwater are seeping into the ocean every day.
The accidents have called into question TEPCO's ability to manage the cleanup effort. They have also prompted the Japanese government to step up its involvement in decommissioning the facility, a process that could take decades.
This photo released by Tokyo Electric Power Co. shows the storage tank that workers determined was overfilled, causing a leak of toxic water, Fukushima, Japan, Oct. 3, 2013.
Japan's Prime Minister Shinzo Abe (in red helmet), wearing a protective suit and mask, is briefed about tanks containing radioactive water by Fukushima Daiichi nuclear power plant chief Akira Ono in Okuma, Sept. 19, 2013.
Japan's Prime Minister Shinzo Abe (R) is briefed about water treatment equipment during his inspection tour of the tsunami-crippled Fukushima Daiichi nuclear power plant, Sept. 19, 2013.
An aerial view shows the tsunami-crippled Fukushima Daiichi nuclear power plant and its contaminated water storage tanks (top), August 31, 2013. (Reuters/Kyodo)
Japan's Nuclear Regulation Authority Chairman Shunichi Tanaka is seen in front of a screen showing the current situation of the contaminated water leakage at Fukushima Daiichi, Sept. 2, 2013.
An aerial view shows workers wearing protective suits and masks working atop contaminated water storage tanks at the Fukushima Daiichi nuclear power plant in this photo taken by Kyodo, August 20, 2013.
Members of a Fukushima prefecture panel, which monitors the safe decommissioning of the nuclear plant, inspect the construction site of the shore barrier, August 6, 2013.
An aerial view shows the No.3 reactor building at the Fukushima Daiichi nuclear power plant, July 18, 2013. (Reuters/Kyodo)
A worker takes radiation readings on the window of a bus at the screening point of the Fukushima Daiichi nuclear power plant, June 12, 2013.
Japan's Economy, Trade and Industry Minister Toshimitsu Motegi, wearing a protective suit and a mask, inspects contaminated water tanks at the Fukushima Daiichi nuclear power plant, August 26, 2013.
A former resident walks past an overgrown garden during a visit to his home in the abandoned town of Namie, just outside the 20 kilometer exclusion zone around the Fukushima Daiichi plant, Nov. 20, 2011.
Mourners in protective suits hold flowers at a memorial ceremony for residents from the town of Okuma, inside the contaminated exclusion zone near the crippled Fukushima Daiichi nuclear power plant, July 24, 2011.
Interior of No. 4 reactor building at the tsunami-crippled Fukushima Dai-chi nuclear power plant, Nov. 8, 2011.
Japanese police officers wearing suits to protect them from radiation carries a victim as another group carries another body while searching for missing people in Minami Soma, Fukushima Prefecture, April 8, 2011.
Smoke rising from Unit 3 of the tsunami-stricken Fukushima Daiichi nuclear power plant, March 21, 2011.