« Back to Energy Insider
Pipeline Safety an Ongoing Concern, Priority for All Segments of Natural Gas Industry
by Christina Nagy-McKenna, Enerdynamics Instructor
In its 2013 list of top 10 gas industry issues, Black and Veatch, a global engineering, construction, and consulting company, reported that safety was cited as the No. 1 issue by all segments of the market: upstream, midstream, downstream, and additional stakeholders.
Distribution utilities, pipeline companies, and regulators are confronted with aging infrastructure that is slowly failing, often with catastrophic consequences. Wear and tear due to corrosion, damage, and stress can be difficult to diagnose given that pipelines are buried under ground and are not visible to inspectors.
While technology exists to assess the strength of most of the 2.6 million miles of gas and liquid transportation pipelines in the U.S. (93 percent of which are used to transport natural gas), some areas are unreachable due to the design and construction of the lines. Additionally, as recent gas pipeline safety cases have demonstrated, records that vastly predate computerized data storage and organization are sometimes inaccurate. This leaves a growing industry with a glaring Achilles heel.
California’s response to tragedy
Four years ago the startling rupture of PG&E’s gas transmission Line 132 in San Bruno, Calif., took the lives of eight residents, injured 58 people, leveled 38 homes, and damaged 70 more. The tragic accident made national news and left many people wondering how such a large pipeline in the middle of a residential neighborhood could suddenly and inexplicable explode. Pictures of the 72-foot-long and 26-foot-wide crater looked more at home on a Hollywood movie set than in a quiet, suburban neighborhood.
The pipeline, put into service in 1948, became the blueprint for aging infrastructure that was not subject to pressure testing requirements of newer pipelines due to age exemptions, and whose as-built drawings did not match its actual construction. Specifically, Line 132 was inaccurately recorded as a seamless steel pipe when in fact it was a longitudinally seam-welded pipe. Accurate record keeping is considered an important part of establishing valid maximum allowable operating pressures (MAOP) for all pipelines.
Since the San Bruno accident, the California Public Utilities Commission (CPUC), PG&E, and other California gas utilities have worked diligently to design and implement new, stringent standards set by the CPUC to prevent another devastating event. Specifically, on June 9, 2011, the CPUC issued a decision that ordered all California natural gas transmission operators to design a plan to test or replace all transmission lines that had not been pressure tested and to present this plan to the CPUC for approval. This order stemmed in part from PG&E’s difficulty locating pressure-testing records for 152 miles of its total 1,805 of transmission pipeline, approximately 8 percent of its system.
The order further specified that all operators provide interim safety enhancement measures including:
- increased pipeline patrols and leak surveys
- pressure reductions
- a prioritization of pressure testing for critical pipelines that had to run at or near their MAOP values at or above 30 percent of its specified minimum yield strength (SMYS)
As of April 2014, PG&E has hydrostatically tested over 565 miles of its pipeline system, and it has replaced close to 90 miles of pipe. The remaining California utilities are also implementing their pipeline safety plans.
Federal measures for pipeline safety
At the same time that the CPUC strengthened rules in California, Congress passed the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011, which was signed by the President in January 2012. Among its objectives, the Act:
- reauthorized the Department of Transportation Pipeline and Hazardous Materials Safety Administration’s (PHMSA) federal pipeline safety programs through 2015
- strengthened safety regulations
- increased civil penalties for violations
- provided for follow-up surveys and reports on safety concerns including the management and replacement of cast iron natural gas pipelines
Despite the new regulations, tragic incidents continue to occur. In March of this year, a gas leak and subsequent explosion leveled two tenements in Harlem and took the lives of eight people. The investigation of this accident is ongoing, but residents reported smelling gas in the days prior to the explosion, and the gas main line to the tenement was an old cast iron pipe – again raising questions about aging infrastructure. During 2005-2013 approximately 2.5 percent of the gas distribution mains in the U.S. were made of cast iron, but 10.5 percent of incidents on gas distribution mains involved cast iron mains. And, in proportion to overall cast iron main mileage, the rate of incidents on cast iron main lines was more than four times that of mains made of other materials.
In February natural gas was the cause of an explosion in Chicago, which injured two women, as well as a fire in Kentucky that injured two people and destroyed two homes. Thus far in 2014, PHMSA, the agency that oversees pipeline safety in the United States, has recorded 73 incidents on gas transmission systems, and 62 occurrences on gas distribution systems. These events have resulted in 14 fatalities and 78 injuries. Data for recent years are equally grim: A five-year average from 2009 to 2013 for fatalities on the gas transmission system is two while on the gas distribution system it is 10.
Thus, it is not surprising that the natural gas industry’s top concern is safety. While there have been fewer gas distribution incidents in the past two years, the number of injuries and fatalities is still high. Additionally, the number of gas transmission accidents has not diminished since 2009. While the investigation of the accident in Harlem is ongoing, it is clear that the industry needs to accelerate maintenance and replacement of infrastructure that is old and, in some cases, simply obsolete in technology and engineering.
For example, during 2005-2013 approximately 2.5 percent of the gas distribution mains in the U.S. were made of cast iron, but 10.5 percent of incidents on gas distribution mains involved cast iron mains. And, in proportion to overall cast iron main mileage, the rate of incidents on cast iron main lines was more than four times that of mains made of other materials.
Three years ago, federal and state regulators took action in response to the San Bruno gas explosion. In addition, U.S. Transportation Secretary Ray Lahood together with the PHMSA issued a “Call to Action” to the regulatory agencies and natural gas pipeline operators to step up the repair and replacement of infrastructure that is considered highest-risk. These are all positive steps toward increased safety, but given the slow rate of reduction of actual number of annual incidents and steady aging of the U.S. natural gas pipeline system, the industry still has work to do.
 CPUC Decision 11-06-017, June 9, 2011, page 26.
 Status Report on NTSB Recommendations to the CPUC, August 2014.
 U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration website, Pipeline Replacement Updates, Cast and Wrought Iron Inventory.
 All Reported Pipeline Incidents, US. Department of Transportation, Pipeline and Hazardous Materials Safety Administration website.
CPUC Approves Pipeline Safety Plan for PG&E; Increases Whistleblower Protections, Press Release Docket No. R. 11-02-019, California Public Utilities Commission, December 20, 2012.
CPUC Judges Issue Decisions in PG&E Pipeline Cases, Levying Largest Safety Related Penalty Ever by CPUC, Press Release Docket No. I. 12-01-007; I. 11-02-016; I. 11-11-009, California Public Utilities Commission, September 2, 2014.
Decision 11-06-017, Decision Determining Maximum Allowable Operating Pressure Methodology and Requiring Filing of Natural Gas Transmission Pipeline Replacement or Testing Implementation Plans, Rulemaking 11-02-019, California Public Utilities Commission, June 9, 2011.
Decision 11-03-047, Order to Show Cause Why Pacific Gas and Electric Company Should Not Be Found in Contempt, and Why Penalties Should Not Be Imposed, for Failure to Comply with Commission Order, Rulemaking 11-02-019, California Public Utilities Commission, March 24, 2011.
Information on Natural Gas Pipeline Safety, California Public Utilities Commission website.
U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration website,
Pipeline Safety Update..
East Harlem Explosion: Gas System Facts, Con Edison Media Relations, March 13, 2014.
N.Y. Building Collapse: Feds Probe Responsiveness of Gas Company, Bruinius, Harry, NatGas Consulting, March 13, 2014.
Order Instituting Rulemaking on the Commission’s Own Motion to Adopt New Safety and Reliability Regulations for Natural Gas Transmission and Distribution Pipelines and Related Ratemaking Mechanisms, Rulemaking 11-02-019, California Public Utilities Commission, February 24, 2011.
Pipelines Explained: How Safe are America’s 2.5 Million Miles of Pipelines? Groeger, Lena, ProPublica, November 15, 2012.
Pipeline Safety Enhance Plan, Southern California Gas Company website.
Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011, Public Law 112-90, January 3, 2012, United States Government Printing Office.
Status Report on NTSB Recommendations to the CPUC, California Public Utilities Commission, August 2014.
Update 2 — Gas Pipeline Explodes in Missouri, No Injuries Reported, Reuters, November 29, 2013.