In some circumstances - for example, where evacuees would have to travel through a plume of hazardous gases - it may be safer for people to take shelter in their homes, schools or places of work.

If you are advised to shelter in place, follow these instructions:

• Get inside as quickly as possible
• Turn off all heating, ventilation and air conditioning systems. Close vents.
• Close all doors, windows, fireplace flues, vents and other openings. If there are any gaps in the weather stripping, use duct tape, plastic wrap and/or aluminum foil to seal the leaks.
• Close drapes, curtains and shades. Stay away from external windows.
• Use stairwells instead of elevators wherever possible.
• Turn on the radio or television for information. You will be advised what the hazardous material is and what the signs and symptoms of overexposure are.
• Use telephones only if you need immediate emergency assistance. You will be directed how to seek medical help outside the evacuation area.