Six people in the government’s foreign technical trainee program worked at the stricken Fukushima No. 1 nuclear power plant until the end of April despite Tokyo Electric Power Co.’s ban on such dispatches.

A TEPCO official on May 1 said the company had failed to sufficiently check the situation concerning workers at the nuclear plant.

The utility in February 2017 said it would not have foreign trainees work at the plant, which has continued to leak radiation since being struck by the Great East Japan Earthquake and tsunami in March 2011.

The six workers were employed by a subcontractor of Tokyo-based Hazama Ando Corp.

They started working at the plant between October and December last year and were involved in construction of an incinerator on the premises to destroy contaminated protective clothing and other materials.

They were not required to wear protective gear against radiation because they worked outside the radiation-controlled area.

“We will ask prime contractors once more to check the status of workers (under their supervision),” the TEPCO official said.

The company said it also intends to check whether other foreign trainees have ended up working at the plant.

The purpose of the foreign trainee program is to pass down skills and expertise that interns can use to help their home countries. However, a number of cases have shown that companies are exploiting the program to obtain cheap labor, sometimes for dangerous tasks.

In March, it was revealed that a Vietnamese trainee was involved in decontamination work in Fukushima Prefecture but had not been told of the potential hazards.

A Justice Ministry official said decontamination work is an inappropriate job for foreign trainees.