My first house used to have oil heat. The tank was underground and we had to get it decommissioned before we sold the house even though it was converted to gas heat long before we bought the place.
My current house has gas heat and I'm guessing that the guys who installed it weren't rocket scientists. In fact, when we had a gas dryer installed in the old house I kind of remember they tested the gas connection by spraying soapy water on it. Not very sophisticated.
My point is there's a human element involved in all this leaky business and with so many homes relying on gas or oil for fuel, we could have a huge exposure of leaking fuel right below our feet.
Doesn't grab headlines like a train on fire though.