FORD 1998 Expedition - Manual (Page 81)

How does the air bag
supplemental restraint system
work?
The SRS is designed to activate
when the vehicle sustains
sufficient longitudinal deceleration.
The fact that the air bags did not
inflate in a collision does not mean
that something is wrong with the
system. Rather, it means the forces
were not of the type sufficient to
cause activation.
The air bags inflate and deflate
rapidly upon activation.
After air bag deployment, it is
normal to notice a smoke-like,
powdery residue or smell the burnt
propellant. This may consist of
cornstarch, talcum powder (to
lubricate the bag) or sodium
compounds (e.g., baking soda) that
result from the combustion process
that inflates the air bag. Small
amounts of sodium hydroxide may
be present which may irritate the
skin and eyes, but none of the
residue is toxic.
Several air bag system
components get hot after
inflation. Do not touch them
after inflation.
Seating and safety restraints
81