Russian medical staff who treated those injured after a small nuclear reactor exploded in the White Sea earlier this month were asked to sign non-disclosure agreements by the Federal Security Service, according to The Moscow Times. Doctors at Arkhangelsk Regional Clinical Hospital recalled that three injured men arrived at the hospital on Aug. 8, naked and wrapped in plastic bags. They claimed no one told the staff that those injured had been involved in a nuclear accident. “No one—neither hospital directors, nor Health Ministry officials, nor regional officials or the governor—notified staff that the patients were radioactive,” a surgeon told the newspaper. “The hospital workers had their suspicions, but nobody told them to protect themselves.” Another doctor told the Times that three FSB agents requested that the staff sign non-disclosure agreements.

The staff working directly with the patients were offered to have tests done, and one doctor was reportedly found to have Caesium-137 in his muscle tissue. The amount and concentration of the radioactive isotope the doctor had in his body is reportedly unknown. Russia’s Defense Ministry has largely downplayed the severity of the explosion in an area where nuclear missiles are regularly tested, initially reassuring residents that radiation levels were “normal,” even as panicked residents stocked up on iodine.