Japan’s government announced on Tuesday (April 13) that it will dump more than a million tons of contaminated wastewater from the Fukushima nuclear power plant into the Pacific Ocean, beginning in two years.

Roughly 1.25 million tons (1.13 million metric tons) of water have accumulated around the Fukushima Daiichi nuclear power plant in northeastern Japan since 2011, after a magnitude-9.0 earthquake and resulting tsunami devastated the region. The twin disasters killed nearly 20,000 people, according to NPR, and caused meltdowns in three of the plant’s six reactors, triggering the worst nuclear disaster since Chernobyl.