In the event of a nuclear explosion, the first 10 minutes are crucial for survival. Immediate action can drastically reduce your risk of exposure to deadly radiation. While no one wants to imagine such a scenario, being informed and prepared is the best defense. This guide outlines the steps you must take to protect yourself and your loved ones if the unthinkable occurs.

Get inside a sturdy building immediately. If you survive the initial blast, your biggest threat is radioactive fallout. Run to the nearest structure with thick concrete walls or a basement—cars, tents, and wooden buildings offer minimal protection. The goal is to put dense material between you and the contaminated outside air. Every second counts, so act quickly and decisively.

Once inside, stay away from windows. Glass provides no protection from radiation and can shatter during the blast, causing injury. Head to the center of the building or, ideally, underground. The more distance and material between you and the fallout, the better. Fallout usually begins to descend within 10–15 minutes after the explosion, so sheltering before then is critical.

Seal yourself in to prevent radioactive dust from entering. Close all windows and doors, turn off ventilation systems, and block gaps with wet towels or tape. Fallout is made of microscopic radioactive particles that can be inhaled or absorbed through the skin. Creating a sealed space drastically reduces your exposure.

If you were outside during the blast, decontaminate immediately. Remove your outer clothing and place it in a plastic bag to eliminate 90% of contamination. Wash with warm water and soap, but avoid scrubbing or using conditioner, which can trap radioactive particles. Do not eat food that was left uncovered, and avoid tap water unless officials confirm it’s safe.

Stay tuned to official updates via a battery-powered or hand-crank radio. Cell service and the internet may be down, but emergency broadcasts will provide life-saving information—such as when it’s safe to leave shelter, how to find clean water, and where to seek help. Do not leave your shelter until instructed; fallout radiation can drop by 80–90% after 24 hours, making it safer to move then.