TOKYO — A man who developed leukemia after working on a cleanup crew at the ruined Fukushima Daiichi nuclear power plant has been awarded workers’ compensation by the Japanese government, in what amounts to the first official acknowledgment that exposure to radiation at the disaster site may have caused cancer.

The Ministry of Health, Labor and Welfare said on Tuesday that the man, whom it did not identify by name, worked from October 2012 to December 2013 installing protective covers over damaged reactor buildings at the site.

More than 40,000 workers have participated in the vast and laborious cleanup effort at Fukushima Daiichi since the plant was struck four and a half years ago by a tsunami, leading to multiple reactor meltdowns and blanketing the area with toxic debris. A number of those workers have since been found to have cancer and are seeking compensation from public insurance programs or the plant’s owner, the Tokyo Electric Power Company, known as Tepco.

The compensation awarded to the man would cover treatment costs by supplementing his standard national health insurance.