Last summer I was working on my bilge pump. I had disconnected the battery before removing my fuel tank from the bilge of my bass boat. I reconnnected the battery to test the connections, but forgot to disconnect the battery before re-installing the fuel tank. The tank had to be tilted back to re-install and I spilled out some gasoline. Shortly after the other side of the alluminum tank made contact with a positive relay and arc'd out. I held the tank in place to prevent another spark and reached across to disconnect the battery. I almost freaked out thinking about what might have happened (fire/explosion, etc.) I thank God above for keeping me safe and consider this a lesson. Even though I've worked on autos/trucks, etc. and always disconnect the battery when doing such things, I got careless. None of us are above basic safety rules and caution.
BE CAREFUL!!