The National Transportation Safety Board (NTSB or the Board) recently released a Safety Study on the need for safety improvements to the natural gas Integrity Management Program (IMP).  The Board concluded that there is no evidence that the occurrence of gas transmission pipeline incidents in highly populated areas have declined since implementation of IMP rules, and that incidents attributed to causes other than corrosion and material defects have increased from 2010 to 2013.  The NTSB also found that the intrastate incident rate in these highly populated areas, called high consequence areas or HCAs, from 2010 to 2013 was significantly higher as compared to interstate transmission lines (27% higher per every 1,000 miles).  Further, despite the emphasis in the IMP regulations on time dependent threats such as corrosion, gas transmission incidents associated with corrosion continue to disproportionately occur on pre-1970 pipelines.

The NTSB initiated this Safety Study in response to three of its own gas transmission accident investigations that cited deficiencies in operator IMPs and PHMSA oversight (i.e., Palm City, Florida; San Bruno, California; and Sissonville, West Virginia).  In making thirty-three findings, the study identified numerous areas for improvement in gas transmission IMPs including, but not limited to:  (1) IM guidance and training to inspectors (finding that existing PHMSA resources are “inadequate”); (2) inappropriate elimination of threats and interactive threats; (3) expanding the use of in-line inspection (ILI) (because it yields the highest per mile discovery of pipe anomalies); (4) elimination of direct assessment as the sole integrity assessment method; (5) evaluating the effectiveness of risk assessment approaches/models; (6) developing minimum operator qualification criteria for all IMP personnel; and (7) improving IMP data collection and reporting (with an emphasis on geospatial data and geographic information systems).

Based on these findings, the Board issued 22 recommendations to PHMSA in the following areas, among others:

  • Evaluate the need for additional IMP inspection guidance;
  • Assess limitations with current process for identifying HCAs and publish results (including a developing national repository for geospatial data);
  • Increase positional accuracy of pipeline attributes and include HCA identification in the National Pipeline Mapping System;
  • Collection of additional information on annual and incident reporting forms (such as method of HCA identification, risk assessment approaches and inclusion of multiple root causes);
  • Evaluate inappropriate elimination of threats, establish minimum criteria, and provide guidance;
  • Update guidance on evaluation of interactive threats and list all threat interactions that require evaluation and acceptable evaluation methods;
  • Evaluate safety benefits of four risk assessment approaches used by operators, disseminate results, and update guidance on the same (focusing on method for weighting factors, consequence of failure calculations, and appropriate risk metrics and methods for aggregating risk along a pipeline);
  • Require that all transmission lines are capable of being assessed by ILI;
  • Identify operational complications that limit the use of ILI and develop methods to eliminate them; and
  • Develop a plan to eliminate the use of direct assessment as the sole integrity method for transmission lines.

Recommendations were also issued to the American Gas Association and the Interstate Natural Gas Association of America (i.e., to collect data on probabilistic risk assessment models and a strategy for increasing the use of ILI), the National Association of Pipeline Safety Representatives (i.e., to work with PHMSA on developing a program to formalize and facilitate increased state to state coordination in IM inspections), and the Federal Geographic Data Committee (i.e., to develop digital spatial data standards and specifications for use by gas transmission operators in HCA identification).

At a minimum, PHMSA is required by law to respond to the above safety study recommendations from the NTSB.  It is likely that the Board’s findings and recommendations will also inform reauthorization of the Pipeline Safety Act later this year and PHMSA’s forthcoming integrity management rulemakings for both natural gas and liquid pipelines.  The last pipeline safety study NTSB conducted was in 2005, concerning SCADA, and the Board has claimed in the past that it resulted in promulgation of the PHMSA Control Room Management regulations.