Less than 10 percent of the work at this nuclear power plant is conducted by those directly employed by Tokyo Electric Power Co. (Tepco). Over 90 percent is done by employees of subcontractors, sub-subcontractors and contractors several times removed. These workers come from a wide range of backgrounds, including some who gave up jobs in local agriculture or fishing, farmers and fishermen who work at the plants during the off-season, day laborers and former coal miners. Some have complicated stories to tell, or not to tell.
Few other workplaces require no experience or skill, and fewer still guarantee anonymity to those hoping to hide their background. Nuclear power firms also benefit from the weak position of such individuals since they are largely spared the obligations of most employers to protect the health and safety of each worker on-site. Japan Times
See also the related story posted here.