Radioactive waste water has been discharged into the Pacific Ocean since the Fukushima Daiichi nuclear disaster, triggered by the 2011 Tōhoku earthquake and tsunami on 11 March 2011 in Japan. Most of the radioactive materials came from immediate leaks into the atmosphere, 80% of which eventually deposited over the Pacific (and over some rivers). Leakage to groundwater has persisted since the disaster and was only first admitted by the nuclear plant in 2013. Water treatment began that year as the "Advanced Liquid Processing System" became operable, which is capable of removing most radionuclides except notably tritium. In 2021, the Japanese cabinet approved the dumping of radioactive water into the Pacific over a course of 30 years.