If an attack warning is issued, Guam residents should take cover quickly — in a concrete structure, preferably underground — and stay there until instructed otherwise, according to a fact sheet titled “Preparing for an Imminent Missile Threat.”

Guam’s Office of Civil Defense began disseminating fact sheets Friday to help residents prepare for a missile attack from North Korea. The guidance includes tips on building an emergency kit, advice on staying put in concrete or brick structures, and reminders about keeping calm.

“Do not look at the flash or fireball — it can blind you,” the missile threat prep fact sheet advises those who are caught outside. “Lie flat on the ground and cover your head.”

The flier also offers guidance on removing radioactive material: “When possible, take a shower with lots of soap and water to help remove radioactive contamination.” But don’t scratch or scrub skin and “do not use conditioner in your hair because it will bind radioactive material to your hair.”

Officials haven’t raised the U.S. territory’s threat level even after Pyongyang laid out plans to strike near the island in the coming weeks, Guam Gov. Eddie Calvo said. He noted that Guam has many buildings made to withstand powerful typhoons, yet he acknowledged that nothing can protect against a thermonuclear attack.