[5] During recovery efforts later in 2018, Russia used three ships, one capable of handling radioactive material from the weapon nuclear core, to bring the missile tested in November 2017 from the seabed of Barents Sea back to the surface.

[13][14][15] Nonproliferation expert Jeffrey Lewis and Federation of American Scientists fellow Ankit Panda suspect the incident resulted from a Burevestnik cruise missile test.

[16][17] However, other arms control experts disputed the assertions: Ian Williams of the Center for Strategic and International Studies and James Acton of the Carnegie Endowment for International Peace expressed skepticism over Moscow's financial and technical capabilities to field the weapon,[18] while Michael Kofman of the Wilson Center concluded that the explosion was probably not related to Burevestnik but instead to the testing of another military platform.

One doctor was found to test positive for Cesium-137, though the levels remain unknown, as the medical staff involved were forced to sign non-disclosure agreements.

[23][24][25] According to an unnamed medical worker, two injured by the explosion died of radiation sickness en route from Arkhangelsk Regional Clinical Hospital (AOKB) (Russian: Архангельская областная клиническая больница (АОКБ)) to treatment in Moscow.

[25][26] Their bodies were sent to Moscow's Burnazyan Federal Medical and Biophysical Center (FMBC) (Russian: ГНЦ Федеральный медицинский биофизический центр имени А. И. Бурназяна ФМБА России).

[25][a] Six persons with severe injuries from the explosion and radiation exposure were delivered to Burnazyan by two medevac flights and ambulances with special plastic seals, with paramedics wearing chemical protective suits, and, because an operating room apron was highly contaminated after an operation, all Arkhangelsk Regional Hospital doctors, nurses, and staff who came into contact with the injured were sent to Burnazyan, too.

[11][46][47] The video by Severodvinsk journalist Nikolai Karneyevich (Russian: Николай Карнеевич) demonstrates gamma radiation levels at 150 metres (490 ft) from the abandoned vessels on the White Sea shore close to Nyonoksa with the reading reaching 186 μR/hour - 15 times higher than natural.

[47][49][50] Over 500 miles (800 km) away, tiny amounts of radioactive iodine, which were collected from 9–12 August, were detected at an air filter station in Svanhovd by Norway's nuclear safety authority.