When working with either pipe joint compound or plumber's putty, there are a few things to keep in mind. Here's are some tips for working with pipe joint compound: Petroleum-based pipe joint compound should not be used with PVC or other plastic pipes because it will deteriorate the plastic...
But when I asked about the adaptors and flex connection gas lines they were putting in (using the channel lock they used as a hammer and for nuts & bolts -- their only tool) they were clueless, no idea whether yellow teflon tape or pipe dope belonged or didn't belong on the gas ...