[9YearLurker]

But are you talking about pipelines like Keystone—or every single gas line into any home across the country?

[PA Engineer]

every single gas line into any home across the country?

All transmission, distribution and service lines fall under the NTSB.

PHMSA Pipeline and Hazardous Materials Safety Administration

The specific regulations for natural gas pipeline safety are HERE under SUBCHAPTER D—PIPELINE SAFETY, Part 192.