In the event of a fuel-related emergency, your best course of action is to:
* Turn the ignition off: This is the most effective way to stop the fuel flow.
* Disconnect the battery's negative terminal: This will completely cut power to the fuel pump. This requires tools.
Important Note: Disconnecting the battery is not a quick action and requires some mechanical aptitude. Addressing a fuel leak requires professional attention. If you suspect a fuel leak, do not attempt to work on it yourself; contact a qualified mechanic or tow truck immediately. Fuel leaks are extremely dangerous.