Off Topic... Boat Explodes at Dock

'before starting it' EDIT!!!!

Boats are frequent insurance fraud / arson cases, but this one doesn’t sound like it because people were on and around the boat.
You’re right - probably fumes ignited. People smell gas and ignore it.

Really scary. I’ve seen this twice over many decades of boating. OP is correct, there is a very deliberate procedure that must be followed when refueling to evacuate gas fumes from the engine compartment and bilge prior to hitting the ignition switch.

I remember from when I owned a boat, the procedure we used when boarding and getting started one of the most important steps was venting the engine compartment. We followed our checklist very carefully.
Nowadays I believe that the newer boats engine compartments have an interface that vents the compartment before the engine can be started.

^if anyone believes you had a boat, I have oceanfront property in Arizona to sell them.

That's why I own a rowboat.

Damn