There are three categories of natural gas pipeline systems, one of which poses much greater risks than the others.
The system with the fewest issues so far gathers gas at wellheads and takes it to processing stations. In Fort Worth and some other Texas towns, these gathering lines have begun to attract public concern, an issue that may increase with development of shale gas fields beneath and near cities and towns in Pennsylvania, New York, Colorado and other states.
The largest part of the system is distribution, the roughly 2.1 million miles of small bore pipes that carry natural gas to homes, offices and other buildings. Damage caused by backhoes and other excavation equipment is the largest danger here, but the risks are primarily to careless operators.
The potentially most dangerous system is the one linking gas gathering and gas distribution, the roughly 300,000 miles of pipelines up to 42-inches in diameter that transports gas long distances. The Pipeline and Hazardous Materials Safety Administration has jurisdiction over about 174,000 miles of this system. The rest do not cross state lines and are regulated by state safety agencies.
December 15, 2010
David Kay Johnston: Corroding Pipelines