After a fire in an isolated farmhouse, firefighters found several small propane tanks and other strong evidence of a recently abandoned "meth lab." if what the firefighters found was a "meth lab," we would say:

we would say whether meth generated from the meth lab caused the fire in the farm house. The methane gas when it comes out it reacts with oxygen and cause fire. It is highly possible that the fir in isolated farmhouse caused by meth.