I've been to 100's of gas leaks in my job as a fire LT. We are issued Streamlight Survivors. I see guys use all kinds of lights.

The gas company guys all carry Maglites, rechargebles.

The exposive range is quite narrow and to reach the L.E.L you would have a ton of gas, the joint would be just loaded.99.9 percent of all gas calls don't reach more than 4-5 percant of the LEL from what I've seen.

Although I have been to one house that blew up killing 2. Again to reach those levels it takes almost a broken pipe flowing for awhile.

Last trick I went for a gas call where someone stole the stove and let the pipe flow open till someone smelled it from the street. The LEL upstairs was I think around 20 percent of the LEL and the place was thick with gas hell it was smelled from outside yet only 20 percent LEL.