I had a licensed natural gas tech/plumber install a new branch line using CSST to a new fireplace. When I am asked him about bonding it, he said he had never heard of that before. From everything thing I've read, bonding seems necessary (to avoid damage to the CSST from lightning strike or otherwise stray electrical charge). What I can't wrap my head around is this: If the gas line is bonded to the electrical panel (circuit breaker service entrance) which is bonded to the water supply from the street (just a lead pipe (yes, we still have lead here) that runs through the ground), how is this different from the gas pipe which already is a metal pipe running through the ground? It seems that the gas pipe is already grounded by virtue of being buried. If I put what seems like an additional ground on the gas pipe, don't I run the risk of other charges on the grounding system running through the gas pipe to discharge instead of the water pipe?
The pipe only needs to be bonded at 1 place, usually this is at the meter. If it is bonded there the entire system is attached to a grounding bond and would be legal.
The gas pipe is bonded to prevent it from becoming electrified by a short. It cannot be used as a grounding electrode but the grounding electrode system needs to be attached someplace after the gas meter. I would check there as that is where the bond is usually located.
If you have lead pipes I would want to drive supplemental ground rods and get rid of the lead pipes (I hope you don’t drink the water). The reason to have a pair of additional driven grounding electrodes is a good idea for what happened to a tract of homes in my area. All the old pipe was removed and new non metallic pipe installed. A customer called because getting shocked. I discovered she had no ground and the pipe was plastic up to the house. Their utility did this to every home and the only grounding electrode was the water pipe. After installing a pair of rods she quit getting shocked. If that same case happened to you your gas pipe would end up being your electrode not safe and a code violation.