that found in an Olympic-size swimming pool. The of water was radioactive enough to be hazardous to nearby staff, and the leak was assessed as Level 3 on the International Nuclear Event Scale. On 26 August, the government took charge of emergency measures to prevent further radioactive water leaks, reflecting their lack of confidence in TEPCO. As of 2013, about of cooling water per day was being pumped into the reactors. Another of groundwater was seeping into the structure. Some of water per day was removed for treatment, half of which was reused for cooling and half diverted to storage tanks. Ultimately the contaminated water, after treatment to remove radionuclides other than tritium, may have to be dumped into the Pacific. TEPCO decided to create an underground ice wall to block the flow of groundwater into the reactor buildings. A $300 million 7.8 MW cooling facility freezes the ground to a depth of 30 meters. As of 2019, the contaminated water generation had been reduced to per day. In February 2014, NHK reported that TEPCO was reviewing its radioactivity data, after finding much higher levels of radioactivity than was reported earlier. TEPCO now says that levels of 5 MBq (0.12 millicuries) of strontium per liter () were detected in groundwater collected in July 2013 and not the 900 kBq (0.02 millicuries) () that were initially reported. On 10 September 2015, floodwaters driven by Typhoon Etau prompted mass evacuations in Japan and overwhelmed the drainage pumps at the stricken Fukushima nuclear plant. A TEPCO spokesperson said that hundreds of metric tons of radioactive water entered the ocean as a result. Plastic bags filled with contaminated soil and grass were also swept away by the flood waters. Contamination in the eastern Pacific In March 2014, numerous news sources, including NBC, began predicting that the radioactive underwater plume traveling through the Pacific Ocean would reach the western seaboard of the continental United States. The common story was that the amount of radioactivity would be harmless and temporary once it arrived. The National Oceanic and Atmospheric Administration measured caesium-134 at points in the Pacific Ocean and models were cited in predictions by several government agencies to announce that the radiation would not be a health hazard for North American residents. Groups, including Beyond Nuclear and the Tillamook Estuaries Partnership, challenged these predictions on the basis of continued isotope releases after 2011, leading to a