Russia”s nuclear agency said Saturday an explosion during missile testing in the Arctic left five of its staff dead and involved radioactive isotopes after a nearby city reported a spike in radiation levels.
Rosatom said the force of explosion on Thursday threw several of its staff from a testing platform into the sea.
The military had not initially said that the accident involved nuclear equipment, but said that radiation levels were normal afterwards.
Nevertheless, officials in the nearby city of Severodvinsk reported that radiation levels briefly increased after the accident.
The incident occurred in the far northern Arkhangelsk region during testing of a liquid propellant jet engine when an explosion sparked a fire, killing two, the defence ministry said in a brief statement.
It was not immediately clear whether those two deaths were included in the five that Rosatom had reported.
Russian state news agencies quoted a defence ministry source as saying both defence ministry and Rosatom employees were killed.
Rosatom said its staff were providing engineering and technical support for the “isotope power source” of a missile being tested.
The missile was being tested on a platform at sea when its fuel caught fire and triggered an explosion, Rosatom said in a statement quoted on Russian television.
Several staff were thrown into the sea by the force of the blast, the nuclear agency said, adding that it only announced the deaths when there was no longer any hope that the employees had survived.
The accident left three more of its staff with burns and other injuries, Rosatom said.
It said staff knew of the “potential risk” of the test.
The authorities initially released few details of the accident at the Nyonoksa test site on the White Sea, used for testing missiles deployed in nuclear submarines and ships since the Soviet era. The defence ministry said six defence ministry employees and a developer were injured, while two “specialists” died of their wounds.
