Here's my 2 cents worthI worked on the construction of the...

Here's my 2 cents worth

I worked on the construction of the DBNGL, I am an NDT tech/supervisor and look at the welds on the pipeline. We used to use xray, now use a 3D ultrasonic scanner.

DBNGL is what's known as a sweet gas pipeline and was built to that welding criteria, small defects of up to 12 mm in length are allowed in the root or initial weld pass, the one the gas comes in contact with. A sour gas pipeline which deals with H2S, hydrogen sulfide is welded to a much stricter spec because of the hydrogen, Its root pass must contain NO VISIBLE WELDING Defects. It is much slower to weld and the defect rate is sky high.
So I would say no they won't be adding hydrogen to the mix, but who knows, the engineers come out with paper fixs all the time.