ALL the comments about drug cooking --- there was an HVAC guy there according to the articles I read.
I can tell you this.
I am not sure what change they have made to gas valves. Our service guy told me but I was not fully paying attention. Our old water heater was 20 years old when we replaced it - never needed a thing. The only reason we replaced it was because the new ones were supposedly so much more efficient. The new ones - we have replaced it once, and the second one has been repaired 4 times. All four times was a gas valve issue....which makes me wonder about the recent explosions, which seem more common to me than they ever were before.