Authorities will issue a shelter-in–place order when there is a chemical or biological hazard in the enviroment. It’s a temporary protective measure when you need to create a barrier between yourself and contaminated air outside:
Bring all family members and pets inside the home.
Close and lock all doors and windows.
Turn off all heating, cooling and ventilation systems.
Close dampers in fireplaces.
Select an interior room in your home and stay there. Duct tape around all doors, windows and electrical outlets in that room.
Take your emergency-supply kit with you.
Listen to radio and television broadcasts for further instructions.
Do not leave your shelter area until local officials give an ALL CLEAR order.
After the ALL CLEAR order is given, open doors and windows.