Metering Regulating System

Metering and regulating stations (M&R) track the volume of natural gas as it is transported and distributed. M&R stations use different meters and other equipment to continuously measure the flow and, if needed, reduce the pressure of gas as it moves through the station.
M&R stations may release methane and other pollutants into the air
through leaks in lines, valves, and connections.

When the Federal Energy Regulatory Commission (FERC) reviews interstate gas pipeline projects, M&R stations are included in the project plans. M&R stations are generally considered to be part of the pipeline system and are not permitted separately, so their oversight falls to pipeline companies and utilities. 
PHMSA has some safety regulations for oil pressure limiting stations and some equipment used at metering stations is subject to US Environmental Protection Agency regulations to reduce emissions of methane and volatile organic compounds.