Ont the Pinto and Nissan Sunny, the top of the tank was the floor of the rear compartment. The filler sheared off and metal tank deformed and split or vented in rear-enders spraying the interior with fuel.
On the Holden and Pontiac the tank is deformable plastic and with anti-surge baffling and mounted under the trunk, with steel between it. A Monaro caught fire late last year. Two drunk guys borrowed a mates' car and reversed it into a pole after losing control on a wet road at ~ 100mph.
The car did catch alight, but it was by then in two big bits, and the driver and passenger escaped with minor injuries....
There is no real history of Holdens exploding in flames, unless the car is totally destroyed.
Crash testing info