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Pipeline Incidents and Mileage Reports

Pipeline System Components

Pipelines stretch more than 2.6 million miles across the US. The majority of these pipelines are for gas distribution (81 percent). Another 324,832 miles of pipeline are used for gas transmission and gathering, which is 12 percent of the total. The remaining miles are used for hazardous liquids, 182,166 miles, or seven percent. Pipeline system components also require operators. For the entire system this amounts to about 2,700, almost half of which operate the gas distribution lines. Another 39 percent handle gas transmission and gathering, while 13 percent manage hazardous liquids.

Aging Infrastructure

Over 50% of the nation's pipelines were constructed in the 1950's and 1960's during the creation of the interstate pipeline network built in response to the huge demand for energy in the thriving post-World War II economy. Some pipelines were built even earlier. Approximately 3% of our gas distribution mains are made of cast or wrought iron and were built in the first half of the 20th century. Over 12% of the nation’s cross-country gas transmission and hazardous liquid pipelines were built prior to the 1950's. Each of these types of pipelines has its own unique age (and even material) distribution. The figure below depicts the percentage of pipelines constructed by decade (50s = 1950’s) for each of the three types of regulated pipelines.

Some of our current pipeline infrastructure was built using materials and welding techniques that – though considered acceptable and state-of-the-art at the time -are no longer used today.
Recent incidents in San Bruno, California and Allentown, Pennsylvania have raised questions in the public's mind about the safety of older pipelines. PHMSA is taking a hard look at the causes and characteristics of these failures to identify means to prevent future incidents. Individual states are also examining the need to accelerate the replacement of high risk pipe to ensure public safety and the reliability of our critical pipeline infrastructure into the future.

Pipeline Incidents with Death or Major Injury

Since 1986 the pipeline incidents causing death or major injuries have declined. The long term trend is an average decline of 10 percent every three years. Pipeline incidents can be caused by a number of factors including corrosion, equipment failure, as well as damage from excavations, incorrect operation, and natural forces. Current available data covers the period from 1991 through 2011.

Pipeline Incidents with Death or Major Injury by Sector

The number of Serious Accidents/Incidents fell 30% in the past five years, despite large increases in the number of both fatalities and injuries. Even though the high consequence accidents/ incidents in 2010 were small in number, they were somewhat catastrophic as compared to the average consequence of a serious accident over past years.

Pipeline Fatalities by Sector

Except for spike in fatalities in 1996, overall, the number of deaths due to pipeline incidents have remained low.

Liquid Pipeline Spills with Environment Consequences

Since 2002 and the number of incidents have decreased overall from 153 down to 116 in 2011.