That wasn't the engine that went boom, but the hydrogen in the gas bags used to provide lift. In any event, yes I understand we've created sufficiently study tanks to contain hydrogen, even in most accidents. There are films going back to the 1960s showing serious crash tests of cars with hydrogen tanks mounted, which got through the tests without leaks. Whether those tanks would survive an airplane crash, rather than a car crash, is a great question and I don't know the answer. But I would hope there's been some additional progress in the intervening sixty-ish years.