Fukushima , Japan ( CNN ) -- This is my first time visiting one of the most dangerous places on earth . The devastated Fukushima Daiichi nuclear plant is isolated from the rest of Japan by police checkpoints , security fences , and barricades . We ride on a bus with a handful of journalists into the highly contaminated `` red zone '' -- the area closest to the plant . It remains a desolate wasteland three years after the meltdown , when Fukushima residents had just hours to grab their belongings and leave . They still have n't come back and likely wo n't be able to for a very , very long time . The only people regularly allowed into the red zone these days are workers with face masks and protective gear . We pass them as they labor in heavy clothing , braving the heat along the roadside , filling black bags with contaminated soil . Dead fields , once full of crops , are now filled with endless rows of those black bags . What makes this part of Fukushima such a frightening place is that you ca n't actually see the danger lurking everywhere . Radioactive water is leaking , soil is contaminated , and workers must brave dangerous conditions as they try to slowly and painstakingly take the power plant apart -- a process expected to take decades . Impact underestimated ? The true scope of the contamination is a subject of debate , with a research team from Fukushima University recently releasing a study that claims the plant operator Tokyo Electric Power Company ( TEPCO ) grossly underestimated the amount of radioactive poison cesium-137 released into the environment . Exposure can heighten the risk of cancer . The team 's report says cesium spewed into the air then fell into the water . TEPCO acknowledges it 's impossible to know for sure how much cesium was released , but the company based its estimate on their best information . Contaminated fish is a huge concern , considering seafood is a staple of the Japanese diet . Researchers told me they do n't believe the risk extends far beyond Japan and the North Pacific Ocean , even though small traces of radioactive ocean water have been detected as far away as Canada . The amounts detected so far are not high enough to cause any harm to humans . Conditions inside the Fukushima plant , though , are extremely dangerous . I had to wear layers of protective gear and a Geiger counter , to detect radiation . My shoes were wrapped in plastic to prevent spreading any radiation from contaminated floors . The plant has thousands of times more radiation than was in the bomb dropped on Hiroshima . Outside , I saw the mangled metal piled up near buildings along the coast that bore the brunt of the 2011 tsunami . It sent a 50-foot wall of water crashing into the power plant . Inside , I watched workers remove a fuel rod in reactor 4 . It is slow , grueling work in a reactor that is fully intact . Reactors 1 , 2 , and 3 melted down and the extensive damage there makes the process even more difficult . It will take decades and billions of dollars to make this place safe again . I saw the control room where workers scribbled notes on the walls after the power went out . The protective gear I was wearing got increasingly hot and uncomfortable as sweat poured down my back and condensation clouded the view through my visor . I can only imagine what it 's like for the workers who wear this gear everyday while they work tirelessly to contain this slow-burning disaster . After leaving Fukushima Daiichi , I felt great relief as I was scanned for radiation exposure and none was detected . But as I rode on the bus out of the red zone , I also felt great sadness for the tens of thousands of people who once lived there . I imagined how powerless I would feel if it was my house or business sitting empty and falling into disrepair , not knowing if it would ever be safe to go home again . INTERACTIVE : How Fukushima changed world 's attitudes to nuclear power .
CNN 's Will Ripley visited the devastated Fukushima Daiichi nuclear plant . The Japanese government has said it will take several months to remove all of the melted fuel from reactors 1 and 2, which were destroyed by a massive earthquake in March 2011. Conditions inside the Fukushima plant are extremely dangerous . It will take decades to make the place safe again .