Labor authorities have determined that a factory worker at a subsidiary of chipmaker Renesas Electronics Corp. in Yamagata Prefecture died from karōshi (death by overwork), the man’s lawyer said Wednesday.

The 38-year-old man, who worked at a plant in the city of Yonezawa, died of a heart attack in January 2017 after working an average of about 80 extra hours per month in the four months before his death.

The subsidiary is Renesas Semiconductor Package & Test Solutions Co., according to the Mainichi Shimbun.

A local labor standards office concluded in December that the man, in charge of plant equipment maintenance, suffered from an excessive workload and fatigue as he responded to trouble even late at night and during holidays. He worked 25 hours of overtime in the week before his death, according to the lawyer.

After returning home shortly after 11 p.m. on Jan. 23, 2017, he took a bath, had dinner and went to bed. He died soon afterwards.

He is survived by his wife and three children. His family is set to claim compensation from the company, the lawyer said.

“My husband, a conscientious man with a strong sense of responsibility, sometimes complained of insomnia and chest pains but could not take leave from work to go to the hospital,” the man’s wife said in a note released to the public.

She expressed her frustration at what she saw as the firm’s lack of sincerity, saying her husband’s employer “has not offered any apology even after his death was recognized to have been caused by overwork.”

Renesas Electronics said in a statement, “We extend our condolences to the deceased employee and his family. Although we recognize no legal violation, we take the labor authorities’ decision seriously and will review our employees’ overtime work hours.”

Death by overwork re-entered the national spotlight after the suicide of Matsuri Takahashi, a Dentsu worker, was recognized as a case of karoshi after it was determined in September 2016 that she had worked 105 hours of overtime in a one month period before showing symptoms of depression. She jumped to her death from her company dormitory in Tokyo on Christmas Day in 2015.

Prime Minister Shinzo Abe’s administration has been tackling work-style reform, in part to curtail excess overtime.