Tokyo (CNN) Eight years after Japan's worst nuclear disaster, the government is not sure what to do with the contaminated water that remains -- but its environment minister says dumping it into the ocean might be the only choice.

To cool fuel cores at the damaged Fukushima nuclear plant, operator Tokyo Electric has pumped in tens of thousands of tons of water over the years, according to Japanese national broadcaster NHK. Once used and contaminated, the water is put into storage.

Now, storage space is running out. And during a televised press conference Tuesday, Japan's environment minister Yoshiaki Harada said he believed the only solution was to "release it into the ocean and dilute it."

"There are no other options," he said.

Decontamination efforts around the plant -- pictured here in 2016 -- are expected to take another two years

However, in a separate meeting that day, Japan's Chief Cabinet Secretary Yoshihide Suga emphasized that the government had not settled on a course of action.

Read More