Drainage pumps at the crippled Fukushima Daiichi Nuclear Power Plant, which suffered critical meltdowns after the 2011 Tōhoku earthquake and tsunami, were overwhelmed on September 9 and allowed contaminated water to flow into the Pacific Ocean. This was the seventh such incident in 2015. Flood waters swept 293 bags of radioactive waste into a nearby river, 171 of which were retrieved by September 13. More than 800 people were isolated in the mountain town of Minamiaizu after the Tateiwagawa River washed away the only highway access to the town.