Seamus J. Wilson wrote:
Is there any difference between the yellow gas and white teflon
plumbing tape?
Seamus J.

The thickness

WHITE-Single density- should only be used on NPT threads up to 3/8 inch.
YELLOW- Double Density- yellow double density is often labeled as "Gas type"
RED-Triple Density: (Note-the container is red but the tape itself appears
as a pale pink color). Presently required on all joints ½" diameter or
greater.
GREEN- Oil Free PTFE tape- Required for use on all lines conveying oxygen
(I.E. -medical oxygen or welding oxygen lines).
COPPER COLOR- contains granules of copper and is to be used as a thread
lubricant but is not approved as a thread sealant. (Generally it is used as
a thread lubricant on bolts or pipe threads for mechanical applications
where no physical seal is required.)