Honda 2001 Civic Owner's Manual page 48

If a seat belt is worn during a crash,
you should have your dealer inspect
the belt, and replace it if necessary.
A belt that has been worn during a
crash may not provide the same level
of protection in a subsequent crash.
The dealer should also inspect the
anchors for damage and replace
them if needed.
Automatic seat belt tensioners that
deployed during a crash must be
replaced.
For information on how to clean your
seat belts, see page 257.
Additional Information About Your Seat Belts
Driver and Passenger Safety