A major aspect of pipeline safety is a sound, comprehensive compliance program, conducted by Regional Offices. To allocate its compliance resources in a manner to maximize the impact on safety, PHMSA uses a computer-based tool, known as the pipeline inspection priority program (PIPP), which ranks pipeline units on system characteristics, filed reports, and accident data. PIPP increases productivity by targeting inspections based on risk.

PHMSA investigates major pipeline accidents to determine whether violations of regulations occurred, whether revisions or additions to the regulations are needed and to ascertaining the cause of an accident. The objectives of a PHMSA investigation are to ensure future integrity of the pipeline and develop a sound basis for any enforcement actions taken.

In addition to their responsibility for overseeing the compliance of interstate operators, the PHMSA regional offices are responsible for monitoring the performance of the state agencies participating in the federal/state pipeline safety program as well as performing inspections of interstate pipeline systems and those intrastate facilities not under state jurisdiction.