Close and lock all doors and windows to the outside. The tighter the seal from the possible danger outside, the better.

Building superintendents should confirm all ventilation systems to 100% recirculation so that no outside air is drawn into the structure. When this is not possible, ventilation systems should be turned off.

Turn off all heating systems.

Turn off all air-conditioners and switch inlets to the "closed" position.

Seal any gaps around window type air-conditioners with tape and plastic sheeting, wax paper, or aluminum wrap/foil.

Turn off all exhaust fans in kitchens, bathrooms, and other spaces.

Close all fireplace dampers.

Close as many internal doors as possible in your home or other building.

Select a room in the building where occupants will be the most comfortable and which is easy to seal off. This room should, if possible, provide access to water, toilet facilities, and adequate room for people to sit or lie down. The room should also have a battery powered radio, snack foods, and bottled water.

Use tape and plastic food wrapping such as Saran Wrap, Handi Wrap etc., or aluminum wrap/foil to cover and seal exhaust fan grilles, range vents, dryer vents, and other openings to the outside to the extent possible. Obvious gaps around external windows and doors should also be sealed.

If the gas or vapor hazard is soluble or even partially soluble in water, hold a wet cloth or handkerchief over your nose and mouth if the gases start to bother you.

For a higher degree of protection, go into the bathroom, close the door, and turn on the shower in a strong spray to "wash" the air. Seal any openings to the outside of the bathroom as best as you can. Don't worry about running out of air to breathe. That is highly unlikely in normal homes and buildings.

If an explosion is possible outdoors, close all drapes, curtains, and shades over windows and stay away from external windows to prevent potential injury from flying glass.

Minimize the use of elevators in buildings. These tend to "pump" outdoor air in and out of a building as they travel up and down.

Tune into the Emergency Alert System Stations "KLVI 560AM" and "KQXY 94.1FM" on your battery operated radio for further information and guidance.