MOSCOW  -   A doctor who helped treat victims of the mysterious nuclear blast in Russia more than two weeks ago has traces of radiation in his muscle tissue, said regional officials, who blamed the readings on his diet rather than the explosion.

“Cesium-137 ... has the feature of accumulating in fish, mushrooms, lichens, algae,” Russian specialists told regional officials on Friday, according to Meduza, an independent Russian media organisation. “With a certain degree of probability, we can assume that this element got into the human body through the products of food.” They said the man was not in danger. Meduza quoted an anonymous medical worker who said the man was asked at the hospital if he had gone on holidays in the past few years. “He said he’d been to Thailand at some point. When they heard this, they said where there’s Thailand, there’s Japan: ‘You must have eaten some Fukushima crabs!’”

More than 100 Russian medical workers have undergone checks after the incident at the Russian navy range in Nyonoksa on the White sea on 8 August, which killed five nuclear engineers, two servicemen and injured six others.

The administration’s latest statement came after Russian media reports claimed dozens of medical workers had been exposed to radiation.

Reports emerged that medical teams at the Arkhangelsk city hospital had not been warned that they would be treating people exposed to radiation and had lacked elementary protective gear. They also said Russia’s security agency had forced the medical workers to sign non-disclosure papers.

The workers, who spoke on condition of anonymity fearing official reprisals, said many doctors and nurses were angry the authorities had put their lives at risk.