You guys really have me thinking bout fuel tank safety although this thread is in the wrong section of the forum.
Moderator some help here?
1. Malleable cell to contain the fuel during a spill and resist punture in case of an impact.
2. No sharp edges in the halo surrounding the fuel cell.
3. Anti siphon type vents and a stopper for the feed line in case of a rollover.
4. Nobody has talked about it but you should have a motion switch that kills the fuel pump power supply like the OEMs use or an oil pressure switch that cuts power if you lose oil pressure.
My solution has 3 of three of the 4 elements.