Russian weather agency Rosgidromet on Tuesday reported that radiation levels in the city of Severodvinsk were 16 times higher than normal after an accident last week during a failed missile test, Reuters reported, citing the TASS state news agency.
The Russian defense military initially said background radiation had remained normal, but Rosgidromet reported levels spiked by four to 16 times.
{mosads}Environmental organization Greenpeace, citing data from the Emergency Situations Ministry, said levels had risen more than 20 times above the normal level, according to a report from Radio Free Europe (RFE).
Pharmacies in the region have reportedly sold out of iodine drops, believed to help protect the thyroid gland from certain types of radiation, RFE noted.
The blast occurred Thursday during a test of a missile engine that used “isotope power sources” on an offshore platform in the Arkhangelsk region, Russian nuclear energy company Rosatom said over the weekend.
The Defense Ministry didn’t initially mention the nuclear element but a top official at the institute told Bloomberg News on Monday that a small nuclear reactor was involved in the explosion.
Rosatom confirmed that five scientists had died in the accidental blast, in addition to the two military personnel previously confirmed dead.
The New York Times reported that U.S. intelligence officials believe the blast may have involved a prototype of the SSC-X-9 Skyfall, a cruise missile powered by a small nuclear reactor that allows it to travel long distances.
Russian President Vladimir Putin introduced the weapon during his state-of-the-nation address last year.
The explosion took place roughly a week after the U.S. formally withdrew from the Intermediate-range Nuclear Forces Treaty, a decades-old arms pact with Russia credited with helping end the Cold War.
President Trump on Monday said his administration is “learning much” following the accident.