Can you use Teflon tape to seal a propane line?

Never seal any threaded gas connections (propane or natural) with Teflon tape.

While Teflon tape works well for plumbing jobs as a sealant to reduce leaks where water would otherwise seep through from the connection, doing so with propane or natural gas is EXTREMELY HAZARDOUS and in some scenarios deadly.

Teflon tape used in gas pipe connections is prohibited in the National Fire Prevention Association (NFPA) fire code. When natural gas or propane is put through gas pipes, the tape can catch fire and cause an explosion. Teflon and similar types of tape were designed for use with plumbing projects, not gas lines; therefore, they are not rated for high-temperature applications.