>>996954Yes. They're sensitive enough to detect low levels of dangerous gases, before they become a major problem for you.
Some have an extended "snout" adapter you can shove into confined spaces to verify no hazardous environment exists prior to entry.
A little common sense (and training if you're in the industry) helps too - if you sampled good and step into a murky mess, you can stir up the bad shit. H2S is pretty notorious for that.
