Fuel is delivered from the fuel farm via the underground hydrant system at 12 x atmospheric pressure. If the connection between the dispenser and the pot were to be disrupted, i.e. a vehicle driving in to it, the resultant jet of fuel would reach about 50 metres, before the automatic detectors noticed the sudden drop in pressure and cut the pumps off. I can think of only one instance where this has happened, in South Africa, I believe, many years ago. There is an emergency hydrant cutoff button at the head of every stand.
IIRC there was a "gusher" at MAN a few years ago but don't know the circumstances