-From Howard R. Elliott, Administrator: Thank you for your January 2, 2018, letter regarding our September 29, 2017, response to the National Transportation Safety Board (NTSB) Safety Recommendations P-17-1 and P-17-2, issued on June 15, 2017. I am pleased that PHMSA's approach to address Recommendation P-17-1 was classified as "Open-Acceptable" by the NTSB, and we will strive to complete our proposed actions. I want to re-address, however, the "Open-Unacceptable" response the NTSB gave our agency's strategy to respond to Recommendation P-17-2. Based on the clarifications provided in your January 2018 letter and subsequent conversations with your staff, we have revised our proposed actions to address P-17-2.
Accident Overview from a Regulatory Perspective: The Centreville, Virginia, petroleum leak from Colonial Pipeline (Colonial) on September 1, 2015, was the result of a corrosion fatigue crack that developed from imposed stresses associated with a previously excavated shallow dent on the pipeline. Colonial had previously examined the dent and did not repair it.
Although this dent did not exceed the repair criteria in 49 CFR 195, PHMSA's performance based Integrity Management (IM) regulations supplement prescriptive safety requirements and set systemic performance requirements for operators. IM is based on practices employed by many safety-oriented organizations, whereby safety is continually improved through an iterative process of collecting data, identifying and prioritizing risks, undertaking corrective actions, and assessing performance. PHMSA requires operators to address risks to pipeline safety based on risk assessment of their own unique operating characteristics that extend beyond PHMSA's prescriptive minimum requirements.
In the 2015 release, it does not appear that Colonial adequately assessed the dent that eventually failed with respect to the unique risk characteristics of their pipeline. Furthermore, Colonial staff twice excavated the pipeline around the failed dent in 1994 and 2002, but since their inspections of the dents did not detect any measurable cracking at those times, the dent that failed and another nearby dent were not repaired. It also appears that Colonial removed any rocks or objects that may have caused the original dents. The removal of the rocks or objects may have unconstrained the dent, allowing this dent to rebound (re-round) and subsequently crack and fail.
Following the accident, PHMSA issued a Corrective Action Order (CAO), CPR 5-2015- 5018H, which required among other safety measures that Colonial review past in-line inspection surveys of this segment, identify dents of similar characteristics, and remediate them. Colonial is currently in compliance with the CAO and has modified its dent repair criteria to reflect lessons learned from the CAO for their entire system, redefined what constitutes an actionable anomaly, and issued an Asset Integrity Directive to project personnel to implement the new repair methodology change.
REVISED RESPONSE TO THE NTSB SAFETY STUDY RECOMMENDATIONS:
Below is PHMSA's revised response to Recommendation P-17-2 as contained in the NTSB accident report, Colonial Pipeline Company Petroleum Product Leak, following the September 21, 2015, Centreville, Virginia, incident.
Response: Concur in part and propose alternative action for the NTSB's consideration. PHMSA agrees with the purpose of the recommendation but does not believe that currently available data on dent-related incidents supports additional regulations beyond PHMSA's existing criteria for pipeline integrity evaluation and repair. In our September 2017 response, PHMSA emphasized that dent-related failures are relatively rare, with the majority of these spills below 100 barrels and occurring on a small number of pipeline systems. PHMSA's accident/incident reports show that from 2001 to 2017, dents were a contributing factor in, on average, only two hazardous liquid accidents and one gas transmission incident per year, out of an average of over 600 accidents/incidents total between all pipeline system types.
The majority of these dent-related hazardous liquid accidents were confined to seven operators' particular pipeline systems, so wider regulations may not be necessary for the majority of pipeline systems. In most cases the causes of these dent-related accident/incidents, including construction, operational, or third party damage type events; material quality; pipeline dimensions; construction quality; and poor dent assessment or remediation issues, are already addressed by PHMSA' s current regulations. PHMSA's current hazardous liquid pipeline regulations require operators to correct conditions that could adversely affect the safe operation of its pipeline system "within a reasonable time" and otherwise make immediate repairs for immediate hazards. Operators are required to analyze the findings of pipeline accidents and failures to determine their causes and take actions to prevent recurrence.4 Additionally, operators must evaluate any conditions identified by an assessment or analysis, including certain dents, that could impair the integrity of the pipeline and schedule the condition for remediation as appropriate. Dents that meet the §195.452(h) repair criteria for evaluation and repair are considered potentially injurious and are therefore "actionable."
PHMSA's statutory mandate "is to provide adequate protection against risks to life and property" and to "prescribe minimum safety standards for pipeline transportation and for pipeline facilities."6 Consistent with this mandate, PHMSA has broad authority to take action against pipeline operators that "operate or maintain its pipeline systems at a level of safety lower than that required by [the regulations]."7 PHMSA's broad statutory authority to require action when dents are discovered is not limited to the repair criteria of§ 195.452(h). That said, we do realize that some of the dents that do fail are well below PHMSA's mandatory repair criteria, and cracking and subsequent failure of those "non-actionable" dents may take years to manifest themselves as failures. Of special concern are "rerounded" dents where the object that caused the initial dent has been removed and the now-unrestrained dent partially rebounds, which can lead to cracking. However, PHMSA believes that properly implemented regulations and additional guidance through focused inspections and an advisory bulletin would address these concerns.
Pipeline operators, as owners of the pipeline infrastructure, are required to know and understand the unique operating environments of each of their pipeline systems. PHMSA strongly encourages operators, at both a company and industry level, to focus on best practice performance and aim beyond the minimum compliance standards established through pipeline safety regulations, to ensure the safety of the public that lives and works around pipelines.
While PHMSA believes that supplementary, site specific (local) leak detection systems can be a powerful tool in mitigating pipeline releases, installing external leak detection systems capable of detecting small releases from dents require both power and access to communication systems in order to provide "real time" leak monitoring. Many miles of hazardous liquid pipelines do not have ready access to power or communication. Also, it may be impractical to install leak detection systems in many locations and an operator's capability to install these systems will vary from pipeline to pipeline. For these reasons, PHMSA believes it would be cost prohibitive to require an external leak sensing device in proximity to all excavated dents that are not repaired.
Prior to issuing regulations requiring leak detection systems, PHMSA would need to perform a cost benefit analysis and gather information on how many pipelines have these capabilities and the average cost of installing these local leak detection systems. PHMSA believes improving operator guidance and compliance with current regulations will be more cost and safety efficient than requiring leak detection systems.
In lieu of additional regulations for dent repair and local leak detection systems and to meet the NTSB's intent and ensure that operators implement the current regulations effectively, PHMSA proposes the following strategies to address NTSB Recommendation P-17-2:
• PHMSA will issue an Advisory Bulletin to remind pipeline operators of the required procedures and remediation to be used when any dents are found, either by In-Line Inspection surveys or during an excavation/exposure of the pipeline, whether in high consequence areas (HCAs) or non-HCAs. The Advisory Bulletin will highlight factors that lead to dent cracking, including dent depth, stress concentration areas, soil conditions, restrained and unrestrained dents, interacting threats such as longitudinal and girth welds near the dent, past and future pressure cycling, and pipe properties including toughness, pipe diameter to wall thickness ratio (D/t) ratio, and seam type and location. The integrity of excavated dents must be addressed per § 195.401 (b ), which requires that operators correct any discovered condition that could affect the safe operation of the pipeline regardless of its location.
• During the course of inspections, PHMSA will encourage operators to modify their procedures, if needed, to repair all excavated dents, particularly those dents that have "rerounded" or are not constrained; alternatively, PHMSA may encourage operators to consider installing leak detection systems where feasible.
• PHMSA will modify our current inspector guidance materials to promote operator evaluation of all excavated dents to verify there are no indications of metal loss, cracking, or stress concentrators. This will be done through actions such as publication of the Advisory Bulletin, post-inspection exit interviews, and enforcement of inadequate dent evaluation and repair procedures. PHMSA believes this approach will result in greater safety benefits than requiring leak detection systems, as the systems require operators to run power and communications to remote areas and may be more costly than evaluating, and if needed, repairing excavated dents.
• To improve PHMSA operator inspections, PHMSA will incorporate the results of shallow dent accident/incident root cause or metallurgical analysis by adding new inspection questions based upon these findings, as a part of our integrated inspection criteria. Adding new inspector questions will help train our inspectors, educate our operators, and help focus resources in this area.
• PHMSA proposes to share these key data items with the Voluntary Information Sharing System Working Group Advisory Committee for consideration to be included in the Recommendation Report to the Secretary of Transportation. PHMSA plans to receive the first draft of the Recommendation Report by December 2018.
PHMSA is committed to continued improvements in safe pipeline operational practices, and we take our responsibility to address all recommendations seriously. We will continue to work with your office in the future as we continue our efforts to ensure the safe, reliable, and environmentally sound operation of the Nation's pipeline transportation system.