The radiation levels at Japan's crippled Fukushima nuclear power plant are now at "unimaginable" levels. 

Adam Housley, who reported from the area in 2011 following the catastrophic triple-meltdown, said this morning that new fuel leaks have been discovered.

He said the radiation levels - as high as 530 sieverts per hour - are now the highest they've been since 2011 when a tsunami hit the coastal reactor. 

"To put this in very simple terms. Four sieverts can kill a handful of people," he explained.

He said that critics, including the U.S. military in 2011, have long questioned whether Tokyo Electric Power Co. (TEPCO) and officials have been providing accurate information on the severity of the radiation. 

TEPCO maintains that the radiation is confined to the site and not a risk to the public. It's expected to take at least $300 billion and four decades to fix it. 

Housley said small levels of radiation are still being detected off the coasts of California and Oregon and scientists fear it could get worse.

"The worry is with 300 tons of radioactive water going into the Pacific every day, what is that doing to the Pacific Ocean?" said Housley.

He added that critics are now questioning whether the radiation has been this severe all along.

Watch the full report above.