What to do in a nuclear attack, wherever you are

In a nuclear attack, drop and cover at the flash, get into the nearest solid building within about 10 minutes, and stay inside for at least 24 hours. The rule is the same everywhere, but the first moves differ at home, at work, in a car and on foot.

For the same advice in time order, see how to survive a nuclear attack. It is general information, not official advice; instructions from your local authorities always come first.

What to do if you are at home

1. At the flash, drop face down, away from windows, behind a solid wall or sturdy furniture. Cover your head and neck. Stay down until the blast wave has passed and things are still.
2. Check for injuries, fire and gas. If the house is on fire, or you smell gas and can't shut it off, go to the nearest other solid building, not to your car.
3. Go to the best spot. In a house with a basement, that is the corner most below ground level. Without a basement, use the most central ground-floor room, such as a bathroom or hallway. In a tall apartment building, go to the centre of the building on a middle floor.
4. Seal the house. Close windows, doors and fireplace dampers, and turn off anything that pulls in outside air.
5. Bring water, medication, phone, radio and pets, and turn the radio on.

If you get a warning before a detonation, go to your shelter spot at once. Don't wait to see whether it is real.

If someone knocks, let them in. Ask them to take off their outer clothing at the door, bag it, and wash exposed skin.

What to do if you are at work

Most workplaces are better shelters than most homes: often large, multi-storey and built of concrete and steel. The hard part is the urge to leave.

1. Drop and cover away from windows and glass partitions, under a sturdy desk or behind a solid interior wall.
2. Follow the workplace emergency plan.
3. Move to the basement or underground car park. Otherwise use the core of the building on a middle floor, such as stairwells, interior corridors and inner rooms. Avoid the top two floors and the ground floor near glass.
4. Ask facilities staff to shut off air handling that draws in outside air, and to close outside doors.
5. Use the stairs, not the lifts. Power may fail and leave you trapped.
6. Do not leave to go home or collect children. Schools have their own shelter plans. Text family that you are safe and staying put.

What to do if you are driving

A car is not a shelter. Federal research finds a vehicle barely halves your radiation dose.

1. At the flash, brake smoothly and stop. You may be temporarily blinded, for seconds in daylight and up to 5 to 10 minutes at night. Turn on your hazard lights.
2. Get down below the window line and cover your head until the blast wave has passed.
3. Pull over, take your keys and emergency bag, and leave the car.
4. Walk to the nearest solid building. Good targets are underground car parks, subway stations, office buildings, shopping centres, hospitals and schools.
5. Cover your nose and mouth while outside. Take off your outer layer at the entrance.

Don't try to outrun the fallout. You can't reliably judge the cloud's path, and roads will be jammed with crashed and abandoned cars.

If no building is in walking range, stay in the car as a last resort. Close windows and vents, set the air to recirculate, and get as low as you can.

What to do if you are outside

Outdoors is the most exposed position, but in most towns a building is a couple of minutes' walk away.

1. Drop to the ground, face down. Tuck your hands under your body and close your eyes. Don't run.
2. Stay down until the blast wave and the return wind have passed.
3. Head for the nearest solid building. In order of preference, that is a subway station, underground car park, basement, large brick or concrete building, then any building.
4. Cover your nose and mouth with a mask, scarf or shirt.
5. If dust, grit or ash starts falling, it is fallout. Get into whatever building is closest.
6. At the door, take off your outer layer and brush off your hair and shoes. Then wash.

If no building is in reach, find the lowest protected spot, such as a ditch, culvert or underpass. Then move to a building as soon as you can.

What happens next, wherever you ended up

Once inside, the steps are the same: go to the best-protected part of the building, decontaminate, and stay inside for at least 24 hours.

Sources

• Ready.gov: Radiation Emergencies
• CDC: What to Do - Get Inside
• FEMA: Planning Guidance for Response to a Nuclear Detonation, 3rd edition
• Lawrence Livermore National Laboratory: Key Response Planning Factors for the Aftermath of Nuclear Terrorism

Questions

Should I drive away after a nuclear explosion?

Almost always, no. A car gives very little protection from fallout, and roads are expected to be blocked by crashes, abandoned vehicles and rubble. Official guidance is to get into a building instead and stay there for at least 24 hours.

Should I pick up my children from school in a nuclear attack?

No. Going outside in the first hours exposes you and them to the highest radiation levels. Schools have their own shelter plans, so the safest choice is for everyone to shelter where they are and keep in touch by text.

Should I let other people into my shelter?

Yes. Being exposed to radiation does not make a person radioactive. Ask new arrivals to remove their outer clothing at the door, bag it, wash their exposed skin and change into clean clothes if possible.