There could be exposed threads at every connection of your assembled torch kit. For your protection, all Red Dragon Vapor Torch Kits include a capsule or packet of pipe thread sealant. Always apply this to all connections (except the P.O.L. fitting to the propane tank) when assembling your torch kit. Always leak test you torch before lighting by spraying soapy water on all connections, with the propane valve open (only a ¼ of a turn) but your torch kit NOT lit. If you have a leak, turn off the propane tank, correct the connection and retest before proceeding to light your torch kit.
Instructional Manual here.