The industry ministry Friday recommended releasing treated radioactive water from the crippled Fukushima No. 1 nuclear plant into the ocean, saying it would be preferable to releasing it into the atmosphere by boiling it.

The government has been exploring ways to dispose of more than 1 million tons of water used to cool the melted-down cores at the Fukushima No. 1 power plant, including groundwater near the site, as the complex is running out of storage space.

The water is being treated using an advanced liquid processing system, or ALPS, before being stored in tanks at the plant. But this does not remove tritium and has been found to leave small amounts of other radioactive materials.

Local fishermen have voiced strong opposition to releasing the water into the ocean, saying consumers will be afraid to buy seafood caught in the area.

Both methods of releasing the water are “realistic options,” the Economy, Trade and Industry Ministry told a government subcommittee Friday, but noted that dumping the water into the ocean would make it easier to monitor radiation levels.

This method could be carried out “with more certainty,” it said, because the plant’s operator, Tokyo Electric Power Company Holdings Inc., already carried out the process, albeit on a much smaller scale, prior to the powerful earthquake and tsunami that triggered the triple meltdown at the Fukushima plant in March 2011.

The ministry has said the health effects of either approach would be minimal, estimating it would result in between 0.052 and 0.62 microsievert annually for a discharge into the ocean, and 1.3 microsieverts if released into the atmosphere. That compares with the 2,100 microsieverts people are exposed to daily in a normal living environment, according to the ministry.

Other methods the subcommittee has considered include injecting the water deep into the ground, solidifying and burying it, and extracting only the hydrogen and releasing it into the atmosphere.

Meanwhile, the ministry stressed the importance of gaining the understanding of the local community before making a decision, and of preventing the spread of misinformation that would raise undue fears.

The amount of the water is increasing by about 150 tons per day and Tepco is fast running out of tanks to store it in. The utility is looking to expand capacity to 1.37 million tons by the end of 2020, but has no plans beyond then.