We have a couple who cleans our house one day a week, and two weeks ago my wife came in two hours they had left I and I came in 40 minutes later. When they had bee cleaning the stove they somehow turned one of the burners on without lighting it. So it was going for at least two hours.
But have propane for the first time (about a year now) and it doesn’t smell like natural gas so my wife couldn’t figure out what it was. She thought it was something that might have burned in the self-cleaning oven. The first thing I asked when I walked in was if she had burned broccoli since that’s what it smelled like. When my nose finally took me to the source I was furious. I can’t imagine what would have happened if they had done this when we were on vacation in October. There’s a pilot light in the fireplace in the family room but fortunately the house is really large and that fireplace is raised a foot and a half higher than the floor.
Someone needs to invent an inexpensive gas detector like a smoke alarm that triggers a shut-off valve.
Propane, that is a problem. I never run into propane, but they do make devices like these, if I had to use it, then I would install both.
http://www.propanedetectors.com/
http://midwestgasequipment.com/seismic.htm