Ground to a gas line? No!
Don't even THINK about using a gas line as an electrical ground strap.
Metal underground gas piping is never approved as a grounding device.
NEVER.
It's against the NEC National Electric Code 250.52(B), The UPC Plumbing Code and The NFPA Fire Code.
If that isn't enoungh, it's dangerous and stupid.
Get it ? NO!