Japan will start releasing treated and diluted radioactive wastewater from the Fukushima Daiichi nuclear plant into the Pacific Ocean as early as Thursday — a controversial but essential early step in the decades of work to shut down the facility 12 years after its meltdown disaster.

Prime Minister Fumio Kishida gave the final go-ahead Tuesday at a meeting of Cabinet ministers involved in the plan and instructed the operator, Tokyo Electric Power Company Holdings, to be ready to start the coastal release Thursday if weather and sea conditions permit.

Kishida said at the meeting that the release of the water is essential for the progress of the plant decommissioning and Fukushima prefecture’s recovery from the March 11, 2011, disaster.

He said the government has done everything for now to ensure the safety, combat the reputational damage for the fisheries and to provide transparent and scientific explanation to gain understanding in and outside the country. He pledged that the government will continue the effort until the end of the release and decommissioning, which will take decades.