The International Atomic Energy Agency (IAEA), an international nuclear task force reporting to the UN, has been in Fukushima since Monday to review the country’s plans to discharge contaminated water into the Pacific Ocean.

Speaking to reporters on Friday, IAEA deputy director general Lydie Evrard said that the taskforce had “made significant progress in its work this week to get a better understanding of Japan's operational and regulatory plans for the discharge of the treated water.”

It has been nearly eleven years since a magnitude 9.0 earthquake triggered a devastating tsunami that slammed into the East coast of Japan. The 15-meter (49.2-foot) high waves crashed into the reactors of the Fukushima Daiichi nuclear power plant, disabling the power supply of three reactor cores. Without power to the coolers, all three cores entered meltdown within days, sending radiation billowing into the atmosphere.

Japan is still dealing with the fallout today. That isn’t an exaggeration: this week saw the first few residents of nearby Futaba go home for the first time in over a decade after local radiation levels were finally deemed low enough for people to return.

However, one problem that needs a solution pretty fast is the destination of the more than a million tonnes (1.1 million tons) of wastewater contained in tanks at the site.

Originally, these tanks held water for cooling the damaged reactors, but levels have been steadily increasing over the years thanks to rainfall and groundwater seepage. The tanks are expected to reach their limit in a matter of months. That’s why the Japanese government announced plans last year to discharge it into the ocean – a move that sparked protest almost immediately due to environmental and tourism concerns.

“We need to remind Japan and other nuclear states of our Nuclear Free and Independent Pacific movement slogan: if it is safe, dump it in Tokyo, test it in Paris, and store it in Washington, but keep our Pacific nuclear-free,” Vanuatu stateswoman and veteran activist of the Nuclear Free and Independent Pacific (NFIP) movement Motarilavoa Hilda Lini said not long after Japan’s announcement. “We are people of the ocean, we must stand up and protect it.”

Despite these fears, the IAEA has endorsed the plan, saying that it is similar to other plants’ wastewater disposal procedures.

The Tokyo Electric Power company, aka Tepco, which operates the plant, claims the water is treated to remove almost all radioactive elements, with only tritium – a form of hydrogen that has two neutrons – remaining. While this is toxic, experts say that the amount in the environment will be negligible when diluted across the entire ocean.

“The optics are terrible, but the Japanese government is actually doing the right thing in releasing treated wastewater from the Fukushima plant into the ocean,” said Curtin University’s Associate Professor of Physics & Astronomy Nigel Marks last year.

“By diluting the tritium/water mixture with regular sea water, the level of radioactivity can be reduced to safe levels comparable to those associated with radiation from granite rocks, bore water, medical imaging, airline travel and certain types of food.”

While the IAEA promised to “listen very carefully to local people’s concerns,”, critics nevertheless oppose the plan, with Shaun Burnie, senior nuclear specialist for Greenpeace East Asia, commenting ahead of Friday’s press release that the IAEA “should be investigating the root cause of the contaminated water crisis and exploring the option of long-term storage and the best available processing technology as an alternative to the deliberate contamination of the Pacific.”

“The IAEA […] has sought to justify radioactive marine pollution as having no impact and safe,” Burnie said. “But the IAEA is incapable of protecting the environment, human health or human rights from radiation risks – that’s not its job.”

For now, the IAEA has been collecting water samples and gathering technical information regarding the water disposal plan – a crucial step, especially considering dangerous isotopes including carbon-14, cobalt-60, and strontium-90 may still remain in the treated wastewater, according to a study published last year. The findings will be published in late April as the first of several reports in a multi-year review.

“Ensuring transparency and objectivity is crucial to the project,” Junichi Matsumoto, a Tepco official overseeing management of the treated water, said this week. “We hope to further improve the objectivity and transparency of the process based on the review.”