Guam officials have issued a fact sheet to the island's 160,000 residents on how best to protect themselves in the event of a nuclear missile attack by North Korea.
"Do not look at the flash or fireball -- it can blind you," said the fact sheet posted on social media Thursday. "Take cover behind anything that might offer protection."
The standard fact sheet prepared by the island's Department of Homeland Security and Office of Civil Defense recalls the advice given to U.S. schoolchildren in the "duck and cover" air raid drills of the 1950s to guard against the Soviet nuclear threat.
The warnings from the U.S. Office of Civil Defense featured the cartoon character "Bert the Turtle."
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Recent U.S. intelligence reports have said that North Korea may have succeeded in miniaturizing a nuclear warhead to fit atop a missile.
In the event that the missiles carried a nuclear warhead, the fact sheet, titled "Preparing For Imminent Missile Attack," tells Guam residents to "build an emergency supply kit" and "make a family emergency plan."
Residents should also "make a list of potential concrete shelters near your home, workplace and school. These places can include basements or the windowless center area of middle floors in multi-level buildings."
Once the missiles hit, "Lie flat on the ground and cover your head," the fact sheet says. "If the explosion is some distance away, it could take 30 seconds or more for the blast wave to hit."
Other instructions include, "When possible, take a shower with lots of soap and water" and "do not scrub or scratch the skin. Do not use conditioner in your hair because it will bind radioactive material to your hair."
The fact sheet continues, "Take shelter as soon as you can, even if you are many miles from ground zero where the attack occurred -- radioactive fallout can be carried by winds for miles. Remember the three protective factors: Distance, Shielding and Time."
Earlier this week, Guam Gov. Eddie Baza Calvo sought to ease the concerns of islanders over the increasingly bellicose statements from President Donald Trump and North Korea.
On Friday, Trump tweeted that the U.S. military is "locked and loaded" against any North Korean threat.
"I want to reassure the people of Guam that currently there is no threat to our island or the Marianas," the governor said.
"My Homeland Security adviser, who is in communications with Homeland Security and the Department of Defense, notes there is no change in the threat level resulting from North Korea events," Calvo said.