What safety measure should be taken when disconnecting a vehicle battery?

Removing the negative terminal first is the recommended safety measure when disconnecting a vehicle battery. This practice significantly reduces the risk of short-circuiting the battery and potential injury. By disconnecting the negative terminal first, you effectively break the circuit, preventing any electrical current from flowing through the battery cables.

If the positive terminal is removed first and a tool accidentally touches a grounded part of the vehicle, it can create a short circuit. This can lead to sparks, electrical shock, or even damage to the vehicle’s electrical system. Hence, the method of removing the negative terminal first is critical for ensuring safety during battery maintenance or replacement.

The other options, while they may have their own safety implications, do not address the specific risk associated with disconnecting battery terminals and thus do not provide the necessary precautions to prevent electrical shocks or short circuits.