Some of the largest and oldest natural gas pipeline systems in the United States originate in the Southwest Region of the United States (Texas, Oklahoma, New Mexico, Louisiana and Arkansas). Over one-third of the nation's Natural Gas Pipeline mileage in the lower 48 states runs through this Southwest region. (U.S. Energy Information Administration). During the 1930s, the first long-distance natural gas trunk-lines were built to deliver natural gas to the Midwest Region from the prolific Hugoton Basin located in the Texas/Oklahoma Panhandles. (U. S. Energy Information Administration)
As these natural gas pipeline systems age, the integrity of those systems becomes a greater concern for people who live or work near an aging natural gas pipeline.
Residents of Bushland, Texas were violently shaken from sleep in the early hours of November 5, 2009, when a 24 inch El Paso Natural Gas pipeline exploded, sending flames 700 feet in the air. Members of one family, whose home was only yards away from the underground line, were injured as they raced to escape the flames. Several other homes in that neighborhood were damaged by the blast and the resulting flames.
On June 7, 2010, a power line construction crew hit an unmarked underground gas line in Johnson County, Texas. The resulting fire and explosion killed one man and injured several others. Only two days later, a similar incident occurred in Lipscomb County, Texas when an excavation crew hit an unmarked gas line. Two men were killed by that explosion and fire. Again on September 9, 2010, a San Bruno, California neighborhood was devastated by a gas line rupture and fire that killed eight people, injured many more, destroyed 38 homes, and damaged 120 other homes.
The Pipeline Safety Improvement Act of 2002 mandates significant changes in the way that the natural gas industry ensures the safety and integrity of its pipelines. Central to the law are the requirements it places on each pipeline operator to prepare and implement an "integrity management program," which among other things requires operators to identify so-called "high consequence areas (HCA)" on their systems, conduct risk analyses of these areas, perform baseline integrity assessments of each pipeline segment, and inspect the entire pipeline system according to a prescribed schedule and specific methods.
The Gas Transmission Integrity Management Rule (49 CFR Part 192, Subpart 0) commonly referred to as the "Gas IM Rule," specifies how pipeline operators must identify, prioritize, assess, evaluate, repair and validate "through comprehensive analyses" the integrity of gas transmission pipelines that, in the event of a leak or failure, could affect High Consequence Areas within the United States.
A November 2008 report by Michael Baker Jr. and Raymond R. Fessler, Ph.D, prepared for the U. S. Department of Transportation Pipeline and Hazardous Materials Safety Administration Office (PHMSA), concluded that "corrosion is one of the leading causes of failures in onshore transmission pipelines." Their study found that corrosion was responsible for 18 percent of the significant incidents in the 20 year period from 1988 through 2008, while excavation damage accounted for 26 percent of significant incidents during the same period.
PHMSA uses specific criteria to identify the incidents that are significant from a pipeline safety viewpoint. An incident is defined as significant if it meets any of the following conditions:
- Fatality, or injury requiring in-patient hospitalization.
- $450,000 or more in total costs, measured in 1984 dollars.
- Highly volatile liquid releases of five barrels or more, or other liquid releases of 50 barrels or more.
- Liquid releases resulting in an unintentional fire or explosion.
But the Gas IM Rule only outlines how pipeline companies must police themselves. There is no governmental oversight in the prevention of a significant incident. The Wall Street Journal reports that California Senators Barbara Boxer and Dianne Feinstein urged federal inspections of intrastate gas pipelines in California -- with a priority on those near residential areas -- following the fatal explosion in San Bruno.