Labor authorities have determined that a car mechanic at the crisis-hit Fukushima No. 1 nuclear power plant died last year due to overwork, an organization advising the man's family said Monday.

Tadaaki Igari, 57, who collapsed while on duty at the complex and was confirmed dead on Oct. 26 last year, had logged over 100 hours of overtime the previous month, according to the consultation center for Fukushima nuclear workers.

Igari was the employee of an auto repair company in Iwaki, around 60 kilometers south of the Fukushima No. 1 plant, and was in charge of the maintenance of vehicles used at the plant. The cause of his death was lethal arrhythmia.

The determination of death from overwork by the Iwaki Labor Standards Inspection Office makes Igari's family eligible for benefits under the workers' compensation program.

According to the center, Igari said he felt unwell after a lunch break at around 1 p.m. on Oct. 26 last year. He was checked by a doctor and rushed to a hospital but was pronounced dead at 2:36 p.m.

Igari's family applied for workers' compensation in March, claiming his average monthly overtime hours exceeded 80 hours in the six-month period before his death.

He usually arrived at his employer's office in Iwaki to punch his time card at around 4:30 a.m. before heading to the Fukushima nuclear plant. Labor authorities are believed to have recognized the travel time as working hours rather than commuting time, according to the center.

Tokyo Electric Power Company Holdings Inc., the operator of the power plant, said it was "not in a position to answer" any questions on the labor authorities' decision.

In 2012, the death from a heart attack of a man from Shizuoka Prefecture while on duty at the post-crisis Fukushima plant was also determined to be related to overwork.