Seen that also - Natural Gas powered vehicles are like electric powered vehicles, You better know what you are doing or you'll get a result like the Peterbuilt service center got. A small gas leak, is all it takes. I wonder if they have the "smelly" additive in the fuel? If that may give a indication or if it was just a surprise leak and boom ? Local Truck repair shop works on compressed Nat gas trucks - they'll likely want to know what's up with this incident . . . . .. .