Who is policing gas transmission pipelines?

Gas transmission pipelines are everywhere. In fact 2 million miles of pipelines run throughout the United States. Click here to read an article about the gas industry is charged with policing itself. Pipeline operators perform their own inspections and file reports for federal officials to review.
This paragraph is alarming.

"There are so many pipelines, not all of them can be done at one time," said Damon Hill, spokesman with the Pipeline and Hazardous Materials Safety Administration, the federal agency that inspects interstate pipelines.
The types of inspection include operation, maintenance and new construction. Some pipelines are tested for internal corrosion.
But there are very few independent inspectors in the field looking at pipes.
"It's more so looking at the records the operators are required to keep," Hill said
PHMSA requires pipeline owners to monitor their pipes for standards set by state and federal laws then file reports on what those self-inspections find.
It's a self-policing world.