A court has rejected a damages suit filed by former fishermen and their families who allege the state hid key records showing they were exposed to radiation from the Pacific hydrogen bomb tests conducted by the United States in 1954.

The Kochi District Court on Friday acknowledged the plaintiffs were exposed to radiation from the blasts on Bikini Atoll in the Marshall Islands but denied the state’s liability.

“We cannot conclude that the state persistently gave up providing support and conducting health surveys to hide the radiation exposure,” said Presiding Judge Osamu Nishimura.

The ruling is the first on a lawsuit demanding damages from the state over the H-bomb tests, the plaintiffs said.

Morimitsu Kajihara, a lawyer for the plaintiffs, said they plan to appeal to a higher court.

“We can’t accept a decision that didn’t acknowledge the (state’s) responsibility for neglecting the fishermen,” he said.

A total of 45 plaintiffs — former fishermen from Kochi Prefecture and family members of deceased fishermen — sued in 2016, seeking damages of around ¥65 million.

The plaintiffs claimed they suffered emotional distress because the Japanese government waited 60 years to disclose radiation records on the Japanese vessels that were present around the test sites on Bikini Atoll, which cost them a chance to seek damages from the United States due to the expiration of the statute of limitations in that time.

They also said the state failed in its responsibility to investigate the matter and provide help to those affected, subsequently depriving them of a chance to receive proper treatment.

The state argued it did not hide the documents and called on the court to reject the damages claims.

Between March and May 1954, when the United States conducted six hydrogen bomb tests, about 550 Japanese fishing boats were operating around the area.

Kazuma Masumoto, an 81-year-old plaintiff who was 17 at the time, recalled that when he returned to Tokyo from Bikini Atoll on his tuna boat, he saw the entire catch thrown out and a dosimeter that exceeded its limit when he was checked.

But Japan stopped investigating the boats in December 1954, and the Japanese tuna trawler Fukuryu Maru No. 5, which was in the fallout zone and saw one of its 23-man crew die months later due to acute radiation sickness, became the sole vessel officially recognized as affected.

Japan and the United States struck a deal under which the U.S. paid $2 million for the injuries and damage sustained as a result of the 1954 nuclear tests without admitting liability. The payment was also agreed on as a “full settlement” of any claims against the United States over the issue.

Matashichi Oishi, an 84-year-old former crew member of the Fukuryu Maru No. 5, said the state sought to “cover up” the real issue by instead putting the Fukuryu Maru into the public spotlight as an obvious reminder of radiation exposure.

According to the complaint, government officials in 1986 told a parliamentary committee they were unable to find documents on ships other than the Fukuryu Maru that had been affected by the nuclear tests.

The health ministry in 2014, however, released records of a radiation survey conducted on 556 vessels, and asserted that no ships were exposed to radiation levels that could damage health.