The operation to clean up the nuclear mess spread by the Fukushima reactor meltdown has been plagued with mismanagement and illegal activity as subcontractors have been cited for a number of violations, including recruiting homeless people to work for below minimum wage. According to a new exposé from Reuters, the problems stem from a network of subcontractors related to Obayashi Corp, the second-largest construction company in Japan.

Arrests throughout the year have plagued the $35 billion cleanup project: 

In the October case, homeless men were rounded up at Sendai's train station by Sasa, then put to work clearing radioactive soil and debris in Fukushima City for less than minimum wage, according to police and accounts of those involved. The men reported up through a chain of three other companies to Obayashi.

The reports states that the three largest crime syndicates in Japan have set up a black market recruiting network under Obayashi. There are at least 19 other major contractors tied to the cleanup in addition to Obayashi. The company has not yet been charged with any wrongdoing.

The structure of the operation lends itself to these kinds of oversights, with a pyramid structure of the largest contractors at the top and smallest at the bottom. Reuters said they found 733 contractors in all. The nuclear waste cleanup bidding process was also less stringent than other public works projects, lacking in some places basic disclosure and certification requirements.

The news is just the latest in a series of hurdles for the plant's cleanup and decommissioning after a series of meltdown following an earthquake in 2011. As of late October, more than 90 million tons of toxic water still had to be dealt with, forcing the government to step up its involvement—and investment—in plant owner Tepco's efforts. Just before Christmas, officials announced that the project would take an extra three years, missing its initial anticipated completion date of March 31, 2014.