[Myrddin]

The gas company may not have a leak, but that doesn’t rule out methane coming up out of the ground from a “natural” source. There is plenty of that going on around Bayou Corne, LA. The meth lab angle is possible too. BATFE should have a look at the site.

[meyer]

The gas company may not have a leak, but that doesn’t rule out methane coming up out of the ground from a “natural” source.

It also doesn't rule out a leak in the customer's equipment or piping. The gas company only owns, at best, up to the gas meter, and more likely, to the "tee" connection where the branch line goes to the house.

How long were these people out of town?