Government officials on the Pacific island have published guidelines on how best to avoid and cope with radiation should Pyongyang make good on its threat to launch four Hwasong-12 rockets into nearby waters.
The guidance, entitled “Preparing for an Imminent Missile Threat”, advises Guam’s 163,000 islanders to aseek out windowless shelters in homes, schools and offices, with concrete “dense enough to absorb radiation”.
It adds: “Do not look at the flash or fireball — it can blind you.”
People caught outside during the blast should “Lie flat on the ground and cover your head.
“If the explosion is some distance away, it could take 30 seconds or more for the blast wave to hit.”
Guam became the unlikely focus of global concern last week after president Donald Trump warned North Korea he would hit them with “fire and fury” if the rogue state attacked the US.
Kim Jong Un’s regime responded by announcing it would be targetting the tiny US territory some 2,175 miles away, and has since announced plans to launch four rockets into the sea surrounding the island.
On Friday, Guam’s Homeland Security advisor George Charfauros said it would take roughly 14 minutes for a missile fired from North Korea to reach the island.
Mr Charfauros sought to reassure residents and tourists that the chances of North Koea successfully striking Guam was minimal, due to the “strategic defense umbrella” set up across the Western Pacific to counter missile attacks.
“Our confidence is it’s point zero zero, zero zero, zero – that’s five zeros – and a one,” the governor’s homeland security advisor, George Charfauros, said on Friday.
“The threat level has not changed. It’s business as usual.”
The governor of Guam, Eddie Baza Calvo, received a phone call from President Trump, who reassured him the island would be safe.
A video of the conversation was posted on the Reublican governor’s Facebook page, and Mr Trump can be heard promising that Guam’s tourism will go up “tenfold” after the crisis ends.