TEPCO says the company found out about it only this month, this year.
But what's more disturbing is what Jiji Tsushin reports in the article below: that the job application was submitted by the boy's relative. The article doesn't say what relationship this relative has to the boy.
From Jiji Tsushin (7/17/2012):
16-year-old boy worked at Fukushima I Nuke Plant, against Labor Standards Law, says TEPCO
TEPCO disclosed on July 17 that a 16-year-old boy had worked from the end of May to early July last year at Fukushima I Nuclear Power Plant. It is against the Labor Standards Law to employ people under the age of 18 to work [this is not exactly correct; more later in the post], and it is the second such case at Fukushima I Nuclear Power Plant since the accident.
According to TEPCO, when the boy's relative applied for the boy to work for a subcontractor of Kajima, the relative falsified the age as 18.
At the plant, the boy was engaged in dismantling the vehicles damaged by the tsunami. He worked for 6 days, and the radiation exposure was 0.45 millisievert, including both internal and external exposures. The falsification was discovered this month when TEPCO [or Kajima?] asked for the [copy of the] boy's health insurance card from the relative in order to cancel worker registration [at the plant].
In Japan, health insurance is mandatory, and the health insurance card is often used as a form of ID.
Under Japan's Labor Standards Law, companies can employ people under the age of 18, provided that:
The company have the applicant submit his/her census-register certificate to verify the age;
The applicant himself/herself enter into labor contract, not the relative(s) on behalf of the applicant;
The applicant's relative(s) cannot receive wages on behalf of the applicant;
The applicant won't be made to work overtime.
The mandatory school education in Japan ends at junior high school. Upon graduation, most students are 16 years of age, and eligible to work. So, the violation in this case may be that:
The relative falsified the age of the applicant so that no age verification would be required (the hiring subcontractor may have colluded in this);
The relative may have entered into the labor contract on behalf of the applicant, which is against the law;
The relative may have received the wages, which is against the law;
The applicant may have worked overtime at the plant, which is against the law.
There is no information about the boy's family's situation, but it must have been dire if the family had to rely on the boy working at Fukushima I Nuke Plant under false papers.