Unfortunately they're not that rare. 4 explosions every 5 days.
I would think anything more undercover would be used. A slow-acting, undetectable poisoning agent.
Evidently it wasn't natural gas but a burried propane bottle in the back yard. We have propane because I want the warmth of gas. We also use a gas water heater. Naturally gas isn't available where I live. We have a 1000 gal above ground tank that we lease. You can only fill it to 80% when it's above ground. You can fill it to 100% when burried but I'd have to purchase it. It's a decent distance from the house but not far enough, about 100' if I had to guess.
Becoming more common as lines installed via boring are creating crossbores where gas lines are running through sewer pipes. Now you end up with a gas line across the interior of a sewer pipe causing an obstacle that catches debris and causes a clog. Plumbers send down a cutter to chop up debris without first sending a camera down like they should and puncture the gas line. Gas leaks out into sewer system and makes its way into the nearest home until...boom.
