The other day I was working in my office and noticed someone walking into my back yard. It turns out that it was a local gas company representative checking the gas meter for leaks. I never even knew they did this; but given the number of leaking meters I have found it sounded like a good idea. As I am sure you know, the only reason Natural gas smells like rotten eggs is so that you will pay attention to it and because without adding odors to it you would never know when your house is about to blow up. Whenever I smell what might be a gas leak, I either look until I find it and/or make sure the gas company or HVAC Company gets called to find the leak and/or make repairs. In the picture below we can see a gas leak blowing bubbles in a "soap test" for leaks.
It is not abnormal to smell a little bit of unburned gas when operating the gas range if the burner doesn't light right away or the knob isn't in the correct lighting position, but odors that hang around for any length of time should be further evaluated. Gas leaks are nothing to mess with. A house full of gas vapors can easily destroy the house and anyone in it. This link to Puget Sound Energy provides a lot of great information about gas leaks and gas safety----and is useful no mater where you live in the country. The Gas Company in your area will no doubt have similar information.
Puget Sound Energy says:
Do...
•1. Leave the building
•2. Use a neighbor's phone to call 911 and then Puget Sound Energy (day or night) toll free at 888 225-5773.
Do not...
•1. Turn on or off any electrical switches
•2. Use the telephone
•3. Smoke
•4. Light a match or do anything that might create sparks
•5. Attempt to put out fires if a gas leak ignites
Charles Buell


Charles, the best advice you offer here -- just get out and call Emergency. Let the pro's remediate the problem. No one needs a dead hero for a homeowner.