NTSB Safety Recommendation P-17-002

NTSB safety recommendation P-17-002.

TO THE PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION: Require operators to either (a) repair all excavated dent defects, or (b) install a local leak detection system at each location where a dent is not repaired, continuously monitor for hydrocarbons, and promptly take corrective action to stop a detected leak.

Priority: CLASS II

Overall Status: Open - Acceptable Response

Issued Date: 2017-06-15

Adopted Date: 2017-06-05

Synopsis: On September 21, 2015, at 12:03 p.m., an employee of Bonefish Grill in Centreville, Virginia, called the Fairfax County 911 Center to report a gasoline odor.1 The Fairfax County Fire and Rescue Department (FCFRD) immediately dispatched units to the restaurant in the Centre Ridge Marketplace shopping center. (See figure 1.) After arriving at the scene, firefighters confirmed everyone had left the restaurant; they established an incident command center, and they began the investigation. They did not detect the presence of flammable vapor inside Bonefish Grill and ruled out a natural gas leak; however, they noted a gasoline odor coming from the storm drains at the shopping center. Firefighters detected the presence of flammable vapor in most of the storm drains behind Bonefish Grill and Chipotle. Flammable vapor in some storm drains in front of Bonefish Grill was as high as 100 percent of the lower explosive limit (LEL); however, no liquid was visible in the storm drains. After establishing that the gasoline did not come from the gas station that was located about 400 feet west of Bonefish Grill and that gasoline was not illegally dumped into a storm drain, firefighters considered that the odor could be coming from a leak in a nearby, buried Colonial Pipeline Company pipeline. Colonial confirmed the pipeline leak 2 days later.

Probable Cause: The National Transportation Safety Board determines that the probable cause of the release of gasoline and other refined petroleum liquids from the Colonial pipeline was a through-wall corrosion fatigue crack that developed at a dent in the pipeline due to residual and operational stress and exposure to the underground environment. Contributing to the accident were vague Pipeline and Hazardous Materials Safety Administration regulations that allowed the dent to remain in the pipeline. Also, contributing to the delay in recognizing the release were the limitations of pipeline Supervisory Control and Data Acquisition systems to detect small pipeline leaks.

Ntsbnumber: DCA15MP002

Report Number: PAB-17-01

Addressee Name: PHMSA

Addressee Status: Open - Acceptable Response

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2017-06-15

Communication Type: Transmittal Letter

Communication Contents: On June 5, 2017, the National Transportation Safety Board (NTSB) adopted its report on the September 21, 2015, pipeline leak at a shopping center in Centreville, Virginia.1 The details of this accident and the resulting safety recommendations may be found in the investigative report, which can be accessed at http://www.ntsb.gov under report number PAB-17/1. As a result of this investigation, the NTSB is issuing four new recommendations, including one to the Association of Oil Pipe Lines and the American Petroleum Institute, one to Colonial Pipeline Company, and the following two recommendations the Pipeline and Hazardous Materials Safety Administration: P-17-001 and P-17-002.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2018-01-02

Communication Type: Official Correspondence

Communication Contents: We disagree with Ms. Pearce’s statement that additional regulations requiring operators to excavate, evaluate, and repair all dent defects would be impracticable under the cost–benefit analysis (CBA) required by the Pipeline Safety Act. We point out that Safety Recommendation P 17-2 does not recommend excavating all dents; rather, it recommends that when a pipeline is excavated for other reasons and dents are found, either the dent be repaired (typically by installing a low-cost, full-encirclement sleeve around the affected area), or a local leak detection system be installed. In our report issuing this recommendation, we said that most of the effort associated with evaluating a dent and returning the pipeline to service with or without a repair arises from the excavation work required to expose and examine the buried pipe. The various accepted dent repair methods allowed by your pipeline regulations provide a permanent repair. Because myriad factors are involved in determining if and when an existing dent will develop a through-wall leak, we believe a more prudent approach is to proceed with dent repair whenever a dented pipe is excavated. Therefore, we believe that including the cost of excavating the dented pipe in a CBA is misleading, because the excavation costs result from whatever valid reason led to the excavation that uncovered the dent. We are concerned that you may not have fully understood the recommendation before concluding that it was not practicable based on the CBA. We also do not believe that the alternative that Ms. Pearce discussed addresses the issue in this recommendation, and we ask that you reconsider your response. Pending your taking the action in Safety Recommendation P-17-2, it is classified OPEN--UNACCEPTABLE RESPONSE.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2018-10-18

Communication Type: Official Correspondence

Communication Contents: We note that, until you complete action on Safety Recommendation P-17-1, you will not have the data you need on dent-related incidents to update the criteria for pipeline integrity evaluation and repair. We understand from your March 15, 2017, letter that you expect to have finished action on P-17-1 by August 2019. In your separate letters responding to Safety Recommendation P-17-2, you emphasized that “dent-related failures are relatively rare, with the majority of the spills below 100 barrels (bbls), confined to seven operators’ particular pipeline systems, so wider regulation may not be necessary for the majority of pipeline systems.” We have reviewed the hazardous liquid (HL) dent-related failure data from 2001 to 2017, and we agree that dent-related failures are relatively rare (averaging 2 of 600 incidents per year), and most of the dent-related failures are less than 100 bbls (31 of 41 leaks). However, we disagree that the failures were confined to seven operators. Although seven pipeline operators had multiple dent-related failures, an additional 16 operators had single dent-related failures. Of the ten dent-related failures with leaks reported over 100 bbls, five leaks were over 1,000 bbls, with the highest reported dent-related leak measuring 8,800 bbls in 2015. A total of 26,359 bbls of HL were lost in 41 dent-related PHMSA accident reports. The average spill per HL accident was 643 bbls (27,006 gallons). You report that Colonial Pipeline Company has complied with Corrective Action Order (CAO) CPR 5-2015-5018H and reviewed past in-line inspection surveys of the segment, identifying and remediating dents with similar characteristics. We have reviewed the 11 page CAO, as amended, of October 22, 2015, which was issued before Safety Recommendation P-17 2, and it does not make clear that Colonial is required to repair all excavated dent defects in its system. Although your staff confirmed that Colonial has repaired all excavated dent defects, the other six operators with multiple leaks, and the 16 operators with single leaks, have not been issued corrective action orders to repair all excavated dent defects. You wrote that your current regulations are sufficient because your broad statutory authority requires pipeline operators to take action when dents are discovered, and is not limited to the HL pipeline regulations repair criteria. We note that you believe it would be cost prohibitive to require that local leak-detection systems be installed at each location where an excavated dent is not repaired because many miles of pipeline are remote and do not have access to power and communication, some operators may be incapable of installing leak-detection systems, and a required cost¬–benefit analysis would be a burden. Further, you believe that compliance with current regulations, improved operator guidance, focused inspections, and an advisory bulletin would address P-17-2 and would be more cost- and safety-efficient than requiring leak-detection systems. We disagree that installing local leak-detection systems in remote areas is impractical. We realize the challenges of being out of range for cellular communications and the power grid; however, in other modes of commercial transportation, such as marine, data systems in remote locations use satellite communications and are solar or wind powered to provide real-time information. You proposed the following five revised actions to satisfy this recommendation: 1. PHMSA will issue an Advisory Bulletin to remind pipeline operators of the required procedures and remediation to be used when any dents are found…The integrity of excavated dents must be addressed per 49 CFR §195.401(b), which requires that operators correct any discovered condition that could affect the safe operation of the pipeline regardless of its location. 2. During inspections, PHMSA will encourage operators to modify their procedures, if needed, to repair all excavated dents…alternatively, PHMSA may encourage operators to consider installing leak detection systems where feasible. 3. PHMSA will modify its 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…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 need, repairing excavated dents. 4. To improve PHMSA operator inspections, PHMSA will incorporate the results…Adding new inspector questions to help train our inspectors, educate our operators, and help focus resources in this area. 5. PHMSA proposes to share the 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. Regarding the first proposed action, if your current regulations and statutory authority are enough to require pipeline operators to act when dents are discovered, then the advisory bulletin’s wording should be simple: “pipeline operators are required to either (a) repair all excavated dent defects,” and easily addressed. We feel that your wording of proposed actions 2 through 5 lacks the gravitas of a requirement, which is what we asked for in our recommendation. For example, for the second proposed action, pipeline operators should be required to modify procedures during inspections, if needed, rather than encouraged. Alternatively, you could require that a local leak detecting system be installed when an excavated dent defect is not repaired. The third proposed action should also require operators to repair all excavated dent defects rather than to promote operator evaluation of all excavated dents to verify there are no indications of metal loss, cracking, or stress concentrators. Safety Recommendation P-17-2 requires pipeline operators to act on all excavated dent defects, but your proposed wording gives pipeline operators a choice about whether and how to act on defects. Installing a leak-detection system at each location where a dent is not repaired is the pipeline operators’ only alternative when not repairing an excavated dent defect. We encourage you to work with pipeline operators to explore satellite communications and solar or wind power for leak-detection systems at remote locations to continuously monitor for hydrocarbons. The fourth and fifth proposed actions are vague, but would be satisfactory if they require operators to either repair all excavated dent defects or install a leak-detection system at each location where a dent is not repaired; pipeline operators should not be given the option to not act on an excavated dent defect. As stated in our January 2, 2018, letter, because of the myriad factors involved in determining if and when an existing dent will develop a through-wall leak, we believe a more prudent approach is to repair a dent whenever it is excavated, which is usually accomplished by installing a low-cost, full encirclement sleeve around the affected area. Alternatively, a local leak detection system could be installed. We do not believe that the language in the alternative actions discussed above is strong enough to address the issue in this recommendation, and we ask that you reconsider your response. Pending a requirement that pipeline operators either repair all excavated dent defects or install a local leak-detection system at each location where a dent is not repaired, Safety Recommendation P-17-2, remains classified OPEN--UNACCEPTABLE RESPONSE.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2022-05-02

Communication Type: Official Correspondence

Communication Contents: We note that you previously proposed addressing this recommendation by incorporating aspects of it into the “Pipeline Safety: Valve Installation and Minimum Rupture Detection Standards” proposed rule, but that, after further consideration, you believe that the repair criteria provisions contained in Safety Recommendation P-17-2 will be best addressed in a future NPRM, “Pipeline Safety: Repair Criteria for Hazardous Liquid Pipelines.” You believe this approach will allow you to further analyze developing technologies and practices, anomaly types, repair timeframes, and engineering-critical assessment methods. We note that you plan to publish the NPRM by December 2022. Your planned NPRM, which will be informed by API RP 1183 and our previous correspondence, may satisfy the intent of this recommendation. Pending our review of your published NPRM to ensure that it requires the repair of dent defects that are revealed upon excavation, or the installation of a local leak detection system, Safety Recommendation P-17-2 is classified OPEN-- ACCEPTABLE RESPONSE.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2020-01-23

Communication Type: Official Correspondence

Communication Contents: We note that you plan to assess the finalized RP 1183, as described in your response to Safety Recommendation P-17-1, and incorporate dent assessment principles and recommendations into your pipeline safety regulations as a part of your “Pipeline Safety: Repair Criteria for Hazardous Liquid Pipelines,” rulemaking. We understand that the publication date for this NPRM will be specified in the spring 2020 DOT regulatory agenda. We further note that you believe that this recommendation may be satisfied through a planned NPRM, “Pipeline Safety: Amendments to Parts 192 and 195 to Require Valve Installation and Minimum Rupture Detection Standards,” which will propose that pressure sensors or transmitters be required at all remote control and automatic shutdown valves to detect ruptures along a pipeline. We note that you planned to publish the proposed rule in August 2019; however it has not yet been published. Although we appreciate your efforts to address this recommendation, we are concerned that there are many contingencies to this proposed course of action that must still be resolved. Accordingly, pending measurable progress or additional detailed information, Safety Recommendation P-17-2 remains classified OPEN--UNACCEPTABLE RESPONSE.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2018-02-21

Communication Type: Official Correspondence

Communication Contents: We classified Safety Recommendation P-17-2 OPEN--UNACCEPTABLE RESPONSE in our January 2, 2018, letter responding to your September 29, 2017, letter.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2022-01-14

Communication Type: Official Correspondence

Communication Contents: -From Tristan H. Brown, Deputy Administrator: PHMSA requests NTSB consider alternative actions to address this recommendation. PHMSA previously proposed to address this recommendation by incorporating aspects of it into the Pipeline Safety: Valve Installation and Minimum Rupture Detection Standards proposed rule. After further review of Recommendation P 17-2, PHMSA believes that the repair criteria provisions will be best addressed in a future NPRM titled Pipeline Safety: Repair Criteria for Hazardous Liquid Pipelines. This approach will allow PHMSA to further analyze developing technologies and practices, anomaly types, repair timeframes, and engineering critical assessment methods. According to the Fall 2021 Unified Agenda and Regulatory Plan, PHMSA plans to publish the NPRM by December 2022. PHMSA understands that NTSB will continue to classify this recommendation as Open— Unacceptable Response until after its review of the associated rulemaking efforts. PHMSA looks forward to NTSB’s comments.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2017-09-29

Communication Type: Official Correspondence

Communication Contents: -From Drue Pearce, Acting Administrator: I am writing to update you on the status of actions taken to-date by the Pipeline and Hazardous Materials Safety Administration (PHMSA) and our intended actions to address the recommendations following the National Transportation Safety Board's (NTSB) accident report, Colonial Pipeline Company Petroleum Product Leak, following the September 21, 2015, Centreville, Virginia, incident. The mission of PHMSA is to protect people and the environment by advancing the safe transportation of energy and other hazardous materials that are essential to our daily lives. PHMSA shares the NTSB's commitment to preventing accidents and saving lives. PHMSA has a long history of cooperating and collaborating with the NTSB, and we take seriously our responsibility to address all of the Board's recommendations. The NTSB accident report on the Centreville, Virginia, petroleum leak identified "the probable cause of the release [ ... ] was a through-wall corrosion fatigue crack that developed at a dent in the pipeline due to residual and operational stress and exposure to the underground environment." Colonial had previously examined the dent and did not find any cracks. Although this dent did not exceed the prescriptive repair criteria in 49 CFR Part 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. PHMSA notes that dent-related failures are relatively rare, with the majority of these spill volumes below 100 barrels and from a small number of pipeline systems. Since the Pipeline Safety Regulations ( 49 CFR Parts 192 and 195) already address risks to pipeline integrity, we believe that new regulations would not efficiently address this issue and that there are not enough dent-related incidents to justify a rulemaking. From 2001to2017, PHMSA's accident/incident reports show that 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 among all pipeline system types.1 The dent-related accident/incidents have been caused in most cases by poor pipeline construction techniques, operational or third party damage events, and improper past remediation associated with other pipeline-specific factors such as pipe materials, wall thickness, and diameter. Additionally, the majority of these hazardous liquid accidents are confined to a small number of operators' particular pipeline systems, so wider regulations may not be necessary for the majority of other pipeline systems. When an operator has a pipeline with a leak or rupture, whether caused by a dent or another pipeline-defect factor, PHMSA reviews the causes of the accident/incident and determines if an order is required to mandate that the operator conduct corrective actions to identify and mitigate integrity issues. Sometimes, these actions include additional pipeline system-specific inspections, different integrity assessment methods, procedural or process changes, training and any other needed remediation techniques to eliminate recurrence of a similar release. In summary, pipeline operators are required to know and understand the unique operating environments and inherent risks of each of their pipeline systems. PHMSA challenges operators to focus on 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. Response: Propose alternative action. PHMSA's current hazardous liquid pipeline regulations already require operators to correct conditions in a high consequence area (HCA) that could adversely affect the safe operation of their pipeline systems "within a reasonable time" under §§ 195.40l(b)(l), and (2) otherwise make immediate repairs for imminent hazards. Operators are also required to analyze pipeline accidents and failures to determine their causes and take actions to prevent recurrence under §195.402(c)(5) and §192.617. Additionally, under 3 § 195.452(h)(4)(iv), operators must evaluate any conditions identified by an assessment or analysis that could impair the integrity of the pipeline and schedule the condition for remediation within the time periods prescribed. With respect to dent conditions, PHMSA currently requires all dents to be remediated in HCAs if they exceed a depth greater than two-percent of the pipeline's diameter iflocated on the top of the pipe or six-percent iflocated at the bottom of the pipe. Any topside dent with a crack or metal loss must also be repaired. These criteria have been mandated by PHMSA since December 1, 2000, and appear to have been generally effective in lowering dent-related spills. As noted above, according to PHMSA data, the hazardous liquid pipeline accident rate from dents is about two per year, with a majority of these discharging under 100 barrels of product. With the advent of new, more sensitive in-line inspection tools, a pipeline operator can now identify many dents in pipeline systems that are much smaller than our current repair criteria. PHMSA believes that, based on currently available information, additional regulations requiring operators to excavate, evaluate, and repair all dent defects would be impracticable under the cost/benefit evaluation required by the Pipeline Safety Act. To promote greater pipeline safety related to dent evaluation and remediation, PHMSA proposes that the NTSB accept the following alternative actions: • Issue an advisory bulletin to pipeline operators concerning procedures and remediation to be used when dents are found, in both HCAs and non-HCAs, highlighting factors that lead to dent cracking, such as 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 such as toughness, pipe diameter to wall thickness ratio (D/t) ratio, a:nd seam type and location; the advisory will also remind operators of their responsibility to consider all available information when evaluating threats and take action beyond the minimal safety requirements to address safety risks; • Incorporate the results of shallow dent accident/incident root cause or metallurgical analyses by educating inspectors on dent risks, providing additional inspector guidance, and focusing our inspections on the use of proper assessment tools, dent evaluation and repair criteria, and remediation (if needed); and, • Work with standards organizations to incorporate any recommended practices developed from ongoing accident/incident root cause or metallurgical analyses that promote increased pipeline safety from improved evaluations of in-service shallow dents. We anticipate completing these actions by August 2019. Regarding the installation of external leak-detection systems, PHMSA's data does not support the suggestion that every dent represents an integrity threat that may result in a leak, and PHMSA does not believe a mandate to put an external leak detection system at every unrepaired dent is warranted. Further, PHMSA believes that the cost/benefit evaluation required by the Pipeline Safety Act would preclude the establishment of a new regulatory requirement for installation of a leak detection system at every dent. For these reasons,

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2018-04-05

Communication Type: Official Correspondence

Communication Contents: -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 dete

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2019-04-01

Communication Type: Official Correspondence

Communication Contents: -From Howard R. Elliott, Administrator: PHMSA proposes that the NTSB consider alternative actions to address this recommendation. On April 5, 2018, after the NTSB categorized PHMSA's initial response to this recommendation as "Open- Unacceptable," PHMSA sent the NTSB a revised recommendation that included alternative actions. On October 18, 2018, we received NTSB's response to our proposed alternative actions, which stated that the recommendation remains "Open- Unacceptable." PHMSA proposes to assess the finalized RP 1183, as described in our response to Recommendation P-17-01, and incorporate principles and recommendations from the standard concerning dent assessment (such as dent shape and depth, diameter/pipe wall thickness ratio, pressure cycling and the effects on fatigue growth) for remediation/repair decisions into our pipeline safety regulations as a part of our "Pipeline Safety: Repair Criteria for Hazardous Liquid Pipelines" rulemak:ing as described in our response to Recommendation P-12-03. PHMSA anticipates publishing the NPRM by June of 2020. We also believe the intent of this recommendation may be achieved through a future NPRM titled "Pipeline Safety: Amendments to Parts 192 and 195 to Require Valve Installation and Minimum Rupture Detection Standards." Through this rulemaking, PHMSA will consider requiring pressure sensors/transmitters at all remote control and automatic shutdown valves for rupture detection along the pipeline. According to the Department of Transportation's (DOT) March 2019 Significant Rulemakings Report, PHMSA currently plans to publish the proposed rule in August 2019 and looks forward to the NTSB's comments.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2019-12-03

Communication Type: Official Correspondence

Communication Contents: -From Howard R. Elliott, Administrator: PHMSA proposed an alternative approach for this recommendation on April 1, 2019, and looks forward to NTSB's response.

Addressee Acronym: PHMSA

Addressee Organization Type: G-Federal Government

Communication Date: 2017-11-13

Communication Type: Official Correspondence

Communication Contents: -From Howard R. Elliott, Administrator: PHMSA sent NTSB a response to this recommendation on September 29, 2017. PHMSA looks forward to NTSB's response.