There isn't a readily accessible emergency fuel pump shutoff switch on a 1997 Chevy Venture (or most passenger vehicles of that era). The fuel pump is controlled electrically, and in the event of a crash, the system will usually shut off automatically through various safety mechanisms (like the inertia switch). There's no manual override intended for everyday use.
If you're dealing with a fuel leak or fire, your priority should be evacuating the vehicle and calling emergency services. Disconnecting the battery negative terminal might be considered, but it's not a guaranteed way to stop fuel flow and should only be attempted if you're trained to do so safely.
