# NTSB Safety Recommendation P-12-011

- **operation:** document
- **citation:** P-12-011
- **title:** NTSB Safety Recommendation P-12-011
- **source type:** guidance
- **agency:** National Transportation Safety Board
- **status:** guidance
- **official:** true
- **published on:** 2012-07-25
- **effective on:** 2012-07-25
- **summary:** TO ENBRIDGE INCORPORATED: Revise your integrity management program to ensure the integrity of your hazardous liquid pipelines as follows: (1) implement, as part of the excavation selection process, a safety margin that conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections; (2) implement procedures that apply a continuous reassessment approach to immed
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**body:**

NTSB safety recommendation P-12-011.

TO ENBRIDGE INCORPORATED: Revise your integrity management program to ensure the integrity of your hazardous liquid pipelines as follows: (1) implement, as part of the excavation selection process, a safety margin that conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections; (2) implement procedures that apply a continuous reassessment approach to immediately incorporate any new relevant information as it becomes available and reevaluate the integrity of all pipelines within the program; (3) develop and implement a methodology that includes local corrosion wall loss in addition to the crack depth when performing engineering assessments of crack defects coincident with areas of corrosion; and (4) develop and implement a corrosion fatigue model for pipelines under cyclic loading that estimates growth rates for cracks that coincide with areas of corrosion when determining reinspection intervals.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 2012-07-25

Adopted Date: 2012-07-10

Overall Date Closed: 2014-11-20

Synopsis: On Sunday, July 25, 2010, about 5:58 p.m., eastern daylight time, a segment of a 30-inch-diameter pipeline (Line 6B), owned and operated by Enbridge Incorporated (Enbridge) ruptured in a wetland in Marshall, Michigan. The rupture occurred during the last stages of a planned shutdown and was not discovered or addressed for 17 hours. During the time lapse, Enbridge twice pumped additional oil (81 percent of the total release) into Line 6B during two startups; the total release was estimated to be 843,444 gallons of crude oil. The oil saturated the surrounding wetlands and flowed into the Talmadge Creek and the Kalamazoo River. Local residents self-evacuated from their houses, and the environment was negatively affected. Cleanup efforts continue as of the adoption date of this report, with continuing costs exceeding $767 million. About 320 people reported symptoms consistent with benzene exposure. No fatalities were reported.

Probable Cause: The National Transportation Safety Board (NTSB) determines that the probable cause of the pipeline rupture was corrosion fatigue cracks that grew and coalesced from crack and corrosion defects under disbonded polyethylene tape coating, producing a substantial crude oil release that went undetected by the control center for over 17 hours. The rupture and prolonged release were made possible by pervasive organizational failures at Enbridge Incorporated (Enbridge) that included the following: Deficient integrity management procedures, which allowed well-documented crack defects in corroded areas to propagate until the pipeline failed. Inadequate training of control center personnel, which allowed the rupture to remain undetected for 17 hours and through two startups of the pipeline. Insufficient public awareness and education, which allowed the release to continue for nearly 14 hours after the first notification of an odor to local emergency response agencies. Contributing to the accident was the Pipeline and Hazardous Materials Safety Administration’s (PHMSA) weak regulation for assessing and repairing crack indications, as well as PHMSA’s ineffective oversight of pipeline integrity management programs, control center procedures, and public awareness. Contributing to the severity of the environmental consequences were (1) Enbridge’s failure to identify and ensure the availability of well-trained emergency responders with sufficient response resources, (2) PHMSA’s lack of regulatory guidance for pipeline facility response planning, and (3) PHMSA’s limited oversight of pipeline emergency preparedness that led to the approval of a deficient facility response plan.

Ntsbnumber: DCA10MP007

Report Number: PAR-12-01

Addressee Name: Enbridge, Inc.

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2014-11-20

Addressee Organization Type: P-Private Industry

Communication Date: 2012-10-22

Communication Type: Official Correspondence

Communication Contents: -From Al Monaco, President and Chief Executive Officer: Enbridge Energy, Limited Partnership ("Enbridge") submits this letter and attachments in response to the National Transportation Safety Board's (NTSB) letter dated July 25, 2012 concerning the NTSB's July 10, 2012 Report on the release of crude oil from Enbridge's Line 6B pipeline near Marshall, Michigan on July 25,2010. We have either already, or will soon be, fully implementing all of the NTSB recommendations. The initiatives outlined in our response have enhanced previous efforts that were in progress before this accident. This includes an undertaking to review and improve our processes by incorporating an Integrated Management System, and revising the processes that will form the basis for our Safety Management System. Enbridge recognizes the critical role the NTSB is entrusted with to investigate transportation accidents to determine probable cause and make recommendations to mitigate the likelihood of recurrence, and we appreciate the significant effort the NTSB has made while investigating the accident on our Line 6B pipeline. Enbridge and the NTSB have a mutual goal in relation to safe operation of pipelines. To this end, Enbridge has been transparent and responsive while serving as a cooperative and integral member to the investigation team. The primary objective throughout the investigation has been to identify root cause and possible contributing factors so that we, and others, can implement appropriate measures to prevent reoccurrence and to continually improve the safety of pipeline operations. From the outset, Enbridge has taken every opportunity to learn from this accident and apply enhancements to the system, processes, procedures and our organizational structure, immediately and throughout the investigative process. We have developed a comprehensive plan to lead these and other safety related initiatives now and in the future, and will continue to utilize our leadership position in the liquids pipeline industry to share learnings and promote safety enhancements. Enbridge prides itself on having a culture that is focused on its values of Integrity, Safety and Respect in support of our communities, the environment and each other. Our employees take great pride in their work and also take responsibility and full accountability for actions when things go wrong. We believe that Enbridge's actions following the Marshall release have demonstrated adherence to these values. We committed to clean up the spill and we have delivered on that promise. In fact, we have received many testimonials that the river is in excellent condition. Enbridge has always emphasized the importance of safety in our operations. The pipeline industry has substantially improved its release performance in the last decade and Enbridge has led the way in that effort. Despite this record, we recognize that no accident is acceptable and continuous improvement is essential as we strive for operational excellence. Enbridge will continue to implement actions and system enhancements, focused on attaining our goal of zero incidents. I can assure you that Enbridge will remain diligent and determined in this regard. Please don't hesitate to contact me if you have any concerns. Enbridge applies continuous learning and improvement to our Integrity Management Program (“IMP”). Incorporating lessons learned and re-assessing the condition of our pipeline system has been an aspect of our IMP for many years and has been demonstrated in our responses to research output, technological advances, formalized internal review and improvement processes, regulatory audits, and investigations into non-conformances and incidents such as pipeline releases. We have addressed the recommendation to implement, as part of the excavation selection process, a safety margin that more conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections in the following manner: 1) We have modified the IMP to implement a more conservative approach in our excavation selection process in order to address uncertainities associated with the sizing of crack defects from in-line inspections (“ILI”). Specifically, Enbridge has implemented adjustments in our IMP to increase the level of conservatism as summarized below: •?Utilize the lesser of nominal wall thickness or the value from an ILI tool, as input into the engineering critical assessment (“ECA”) calculation. •?Enbridge no longer uses crack profile information for the depth of crack features. Instead, the maximum value of the depth bin is now being used as the starting point for crack depth estimation. •?Enbridge now accounts for crack tool tolerances / uncertainty by adjusting the depth estimation by a minimum of one tool tolerance. We have addressed the recommendation to implement procedures that apply a continuous reassessment approach to immediately incorporate any new relevant information as it becomes available and reevaluate the integrity of all pipelines within the program in the following manner: 2) We created a team dedicated to a Quality Management Program (“QMP”) for integrity activities (i.e., procedures, training, audits and change management) that provides increased resources and leadership for the development and implementation of enhanced processes. Additionally, increased resources and capacity are now positioned for conducting integrity engineering assessments and strengthening of subject matter expertise related to welding, coatings, cathodic protection, repair techniques, failure models – all aspects that can support an enhanced integrity system continuous re-assessment process. 3) We implemented updated ILI data flow and quality assurance processes including formalized communication of any unreported defects that meet the detection threshold back to the ILI vendor with a documented investigation and review. 4) We integrated ILI root cause analysis of accidents into pipeline integrity programs. 5) Building upon processes already implemented, we will complete an audit and process review on the ILI vendors’ analysis processes with the objective to confirm implementation of lessons learned and to identify any additional opportunities for improvement. 6) We are preparing and implementing a Technology Improvement Plan with Enbridge ILI vendors including the incorporation of new technologies (e.g., EMAT). 7) We will conduct a comprehensive review of past Enbridge failures where ILI performance was identified as the root cause. 8) We are in the process of conducting a reliability engineering analysis of the effectiveness of hydrotesting in conjunction with ILI utilizing results from recently hydrotested Enbridge pipelines. 9) We will conduct an independent expert review of Enbridge ILI verification processes to ensure continued compliance with the new version of API 1163 expected in 2012. 10) We are reviewing current crack ILI reporting requirements and identifying opportunities to increase reporting parameters in order to improve interpretation of the results. 11) We will organize an industry review to develop the protocols for the overlay of multiple ILI data sets so as to improve integrity threat integration methods. 12) We will continue to participate and lead in industry initiatives to define standards and protocols for crack identification technology and integration of ILI data improvements. We have addressed the recommendation to develop and implement a methodology that includes local corrosion wall loss in addition to the crack depth when performing engineering assessments of crack defects coincident with areas of corrosion in the following manner: 13) We developed a methodology to ILI data overlay and assessment actions and integrated such processes into the Enbridge IMP. In particular, improvements have been made in our excavation selection criteria, crack depth est

Addressee Organization Type: P-Private Industry

Communication Date: 2014-01-15

Communication Type: Official Correspondence

Communication Contents: -From Al Monaco, President and CEO: Enbridge Energy, Limited Partnership ("Enbridge") submits this letter and attachment as an update to our previous letter of October 22, 2012 and in response to the National Transportation Safety Board ("NTSB") letter dated July 25, 2012. Over the past year, Enbridge has made great progress in relation to implementing enhancements in the areas of safety and operational reliability. Our focus remains on delivering energy safely and reliably. As such, of the 47 commitments we made in our correspondence of October 22, 2012, 45 have been completed (some have ongoing reviews and implementations) and we expect the final two commitments to be completed by the end of 2014. In addition to the commitments made over a year ago, we have taken additional steps to enhance our safety performance and operational reliability. In 2013, Enbridge appointed a Senior Vice President of Enterprise Safety and Operational Reliability reporting directly to me. A key responsibility of this role is to coordinate a consistent approach across all of Enbridge's business activities to build, share, and promote industry-leading safety practices and culture. Throughout the past year, we continued, through communications and training programs, to actively involve our employees and contractors in achieving our goal of zero incidents – which we call our "Path to Zero". As such, we have provided additional guidance to our workforce through the establishment of Health & Safety Principles that supplement our existing Lifesaving Rules. To further our progress, one of our key initiatives in 2013 was to conduct an enterprise-wide safety perception survey to measure our advancements in relation to safety culture. More than 90% of Enbridge employees participated in the survey, a strong indicator on its own of the level of employee engagement in meeting our safety objectives. That survey, which is evaluated by DuPont, found that tremendous progress occurred in all aspects of safety (leadership, structure, processes and actions), such that Enbridge has achieved the Independent Stage of Safety Culture - a positive measure of the relative strength of our safety culture. Measuring our progress is important to us and to that end, Enbridge retained an independent consultant to verify and make suggestions for improvements in relation to pipeline integrity, leak detection, and public safety. That is in addition to the ongoing regular audits and inspections conducted by our various regulatory agencies. All of the information provided through regulatory or independent audits, is useful to Enbridge and our industry in order for us to all continue down the Path to Zero incidents. Finally, Enbridge has actively participated and presented in numerous industry and regulator led initiatives to advance industry safety, such as the National Energy Board Safety Forum and API's quarterly Hazardous Liquid Pipeline Shared Practices Virtual Tailgate conferences. As discussed earlier, Enbridge has made significant strides in the area of safety culture and performance and I am proud of what we have been able to accomplish during the past year. However, as I indicated previously, Enbridge will remain diligent and is determined to continually improve our safety culture, performance and to lead industry in safety best practices. As we continue on our Path to Zero, we will continue to improve our safety processes through the use of management systems, by monitoring our progress, and by seeking out opportunities to enhance our risk management processes. I trust the attachment provides a satisfactory update and I would ask that you contact me directly should you have any questions in relation to our update. P-12-011: Enbridge Response: Enbridge applies continuous learning and improvement to our Integrity Management Program (“IMP”). Incorporating lessons learned and re-assessing the condition of our pipeline system has been an aspect of our IMP for many years and has been demonstrated in our responses to research output, technological advances, formalized internal review and improvement processes, regulatory audits, and investigations into non-conformances and incidents such as pipeline releases. We have addressed the recommendation to implement, as part of the excavation selection process, a safety margin that more conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections in the following manner: 1) We have modified the IMP to implement a more conservative approach in our excavation selection process in order to address uncertainities associated with the sizing of crack defects from in-line inspections (“ILI”). Specifically, Enbridge has implemented adjustments in our IMP to increase the level of conservatism as summarized below: •?Utilize the lesser of nominal wall thickness or the value from an ILI tool, as input into the engineering critical assessment (“ECA”) calculation. Completed. •?Enbridge no longer uses crack profile information for the depth of crack features. Instead, the maximum value of the depth bin is now being used as the starting point for crack depth estimation. Completed. •?Enbridge now accounts for crack tool tolerances / uncertainty by adjusting the depth estimation by a minimum of one tool tolerance. Completed. Enbridge Response: We have addressed the recommendation to implement procedures that apply a continuous reassessment approach to immediately incorporate any new relevant information as it becomes available and reevaluate the integrity of all pipelines within the program in the following manner: 2) We created a team dedicated to a Quality Management Program (“QMP”) for integrity activities (i.e., procedures, training, audits and change management) that provides increased resources and leadership for the development and implementation of enhanced processes. Additionally, increased resources and capacity are now positioned for conducting integrity engineering assessments and strengthening of subject matter expertise related to welding, coatings, cathodic protection, repair techniques, failure models – all aspects that can support an enhanced integrity system continuous re-assessment process. Completed. 3) We implemented updated ILI data flow and quality assurance processes including formalized communication of any unreported defects that meet the detection threshold back to the ILI vendor with a documented investigation and review. Completed. 4) We integrated ILI root cause analysis of accidents into pipeline integrity programs. Completed. 5) Building upon processes already implemented, we will complete an audit and process review on the ILI vendors’ analysis processes with the objective to confirm implementation of lessons learned and to identify any additional opportunities for improvement. Completed. 6) We are preparing and implementing a Technology Improvement Plan with Enbridge ILI vendors including the incorporation of new technologies (e.g., EMAT). Completed. 7) We will conduct a comprehensive review of past Enbridge failures where ILI performance was identified as the root cause. Completed. 8) We are in the process of conducting a reliability engineering analysis of the effectiveness of hydrotesting in conjunction with ILI utilizing results from recently hydrotested Enbridge pipelines. This work is ongoing and has a target completion of end of Q1 2014. 9) We will conduct an independent expert review of Enbridge ILI verification processes to ensure continued compliance with the new version of API 1163 expected in 2012. Completed. 10) We are reviewing current crack ILI reporting requirements and identifying opportunities to increase reporting parameters in order to improve interpretation of the results. Completed. 11) We will organize an industry review to develop the protocols for the overlay of multiple ILI data sets so as to imp

Addressee Organization Type: P-Private Industry

Communication Date: 2014-07-23

Communication Type: Official Correspondence

Communication Contents: -From Al Monaco, President and CEO: On July 25, 2012 the National Transportation Safety Board ("NTSB") issued safety recommendations to Enbridge Energy, Limited Partnership ("Enbridge") as a result of the investigation of the July 25, 2010 pipeline incident. Enbridge provided an initial response to the NTSB recommendations on October 22, 2012 and a subsequent update on January 15, 2014, to which the NTSB responded on March 21, 2014. The purpose of this letter is to provide an interim update on the remaining open recommendations (P-12-11 , P-12-1 3, and P-12-15). Enbridge continues to implement enhancements in the areas of safety and operational reliability. Our focus remains on delivering energy safely and reliably. Of the 47 identified commitments that address the NTSB's recommendations, Enbridge is pleased to report that, 45 are complete and 1 is substantially complete. I expect the final commitment in relation to conducting a reliability engineering analysis of the effectiveness of hydrostatic testing in conjunction with in-line inspection tools (ILl), based on Enbridge's most recent hydrostatic tested pipelines, to be complete prior to year-end 2014. The attached document summarizes the status of each item in the open recommendations. Additionally, we provide the following information to address items raised in your letter of March 21, 2014. Recommendation P-12-11: The NTSB requested copies of Enbridge's Quality Management Procedures and the new corrosion fatigue model. Enbridge submits the attached document "NTSB Response - PI Quality Management". This document provides an overview of our Integrity Management System (IMS-09) which our Quality Management System department within Pipeline Integrity manages. The complete version of IMS-09 can be viewed through our secure Merrill Data site at your convenience. Additionally, Enbridge submits the attached document titled "NTSB Corrosion Fatigue IR" to address the request of the new corrosion fatigue model. P-12-11: Revise your integrity management program to ensure the integrity of your hazardous liquid pipelines as follows: (1) implement, as part of the excavation selection process, a safety margin that conservatively takes into account the uncertainties associated with the sizing of crack defects from inline inspections; (2) implement procedures that apply a continuous reassessment approach to immediately incorporate any new relevant information as it becomes available and reevaluate the integrity of all pipelines within the program; (3) develop and implement a methodology that includes local corrosion wall loss in addition to the crack depth when performing engineering assessments of crack defects coincident with areas of corrosion; (4) develop and implement a corrosion fatigue model for pipelines under cyclic loading that estimates growth rates for cracks that coincide with areas of corrosion when determining reinspection intervals. Enbridge Response: Enbridge applies continuous learning and improvement to our Integrity Management Program (“IMP”). Incorporating lessons learned and re-assessing the condition of our pipeline system has been an aspect of our IMP for many years and has been demonstrated in our responses to research output, technological advances, formalized internal review and improvement processes, regulatory audits, and investigations into non-conformances and incidents such as pipeline releases. We have addressed the recommendation to implement, as part of the excavation selection process, a safety margin that more conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections in the following manner: 1) We have modified the IMP to implement a more conservative approach in our excavation selection process in order to address uncertainities associated with the sizing of crack defects from in-line inspections (“ILI”). Specifically, Enbridge has implemented adjustments in our IMP to increase the level of conservatism as summarized below: •?Utilize the lesser of nominal wall thickness or the value from an ILI tool, as input into the engineering critical assessment (“ECA”) calculation. Completed. •?Enbridge no longer uses crack profile information for the depth of crack features. Instead, the maximum value of the depth bin is now being used as the starting point for crack depth estimation. Completed. •?Enbridge now accounts for crack tool tolerances / uncertainty by adjusting the depth estimation by a minimum of one tool tolerance. Completed. Enbridge Response: We have addressed the recommendation to implement procedures that apply a continuous reassessment approach to immediately incorporate any new relevant information as it becomes available and reevaluate the integrity of all pipelines within the program in the following manner: 2) We created a team dedicated to a Quality Management Program (“QMP”) for integrity activities (i.e., procedures, training, audits and change management) that provides increased resources and leadership for the development and implementation of enhanced processes. Additionally, increased resources and capacity are now positioned for conducting integrity engineering assessments and strengthening of subject matter expertise related to welding, coatings, cathodic protection, repair techniques, failure models – all aspects that can support an enhanced integrity system continuous re-assessment process. Completed. 3) We implemented updated ILI data flow and quality assurance processes including formalized communication of any unreported defects that meet the detection threshold back to the ILI vendor with a documented investigation and review. Completed. 4) We integrated ILI root cause analysis of accidents into pipeline integrity programs. Completed. 5) Building upon processes already implemented, we will complete an audit and process review on the ILI vendors’ analysis processes with the objective to confirm implementation of lessons learned and to identify any additional opportunities for improvement. Completed. 6) We are preparing and implementing a Technology Improvement Plan with Enbridge ILI vendors including the incorporation of new technologies (e.g., EMAT). Completed. 7) We will conduct a comprehensive review of past Enbridge failures where ILI performance was identified as the root cause. Completed. 8) We are in the process of conducting a reliability engineering analysis of the effectiveness of hydrotesting in conjunction with ILI utilizing results from recently hydrotested Enbridge pipelines. In progress with a target completion of end of Q3 2014. 9) We will conduct an independent expert review of Enbridge ILI verification processes to ensure continued compliance with the new version of API 1163 expected in 2012. Completed. 10) We are reviewing current crack ILI reporting requirements and identifying opportunities to increase reporting parameters in order to improve interpretation of the results. Completed. 11) We will organize an industry review to develop the protocols for the overlay of multiple ILI data sets so as to improve integrity threat integration methods. Completed. 12) We will continue to participate and lead in industry initiatives to define standards and protocols for crack identification technology and integration of ILI data improvements. Completed. Enbridge Response: We have addressed the recommendation to develop and implement a methodology that includes local corrosion wall loss in addition to the crack depth when performing engineering assessments of crack defects coincident with areas of corrosion in the following manner: 13) We developed a methodology to ILI data overlay and assessment actions and integrated such processes into the Enbridge IMP. In particular, improvements have been made in our excavation selection criteria, crack depth estimate process, and the wall thickness value used in the crack engineer

Addressee Organization Type: P-Private Industry

Communication Date: 2014-10-15

Communication Type: Official Correspondence

Communication Contents: -From Al Monaco, President and CEO: On July 25, 2012 the National Transportation Safety Board ("NTSB") issued safety recommendations to Enbridge Energy, Limited Partnership ("Enbridge") as a result of the NTSB's investigation of Enbridge's July 25, 2010 pipeline incident in Marshall, Michigan. Enbridge has provided several updates, the latest of which was provided July 23, 2014. This letter provides a final status update on the remaining open recommendations (P-12-11 and P-12-13). As energy is essential for our society and lifestyles, Enbridge's purpose is to deliver that energy safely and reliably, every day. As such, we continue to press forward with continual improvements to our processes and procedures. We are pleased to report that we have now completed each of the 47 recommendations made by the NTSB. Specifically, Enbridge has completed its reliability engineering analysis of the effectiveness of hydrostatic testing in conjunction with in-line inspection tools (Ill), based on Enbridge's most recent hydrostatic tested pipelines. As this analysis is a core part of our Integrity Management System, it will be subject to regular review and continual improvement processes. The completion of this document fulfills the remaining outstanding requirement of recommendation P-12-11. Furthermore, since the July 23, 2014 update, Enbridge has successfully completed the Lakehead System Leak Detection Instrumentation Improvement project that began in 2011. The completion of this significant project fully responds to recommendation P-12-13. We will continue to review and implement appropriate leak detection instrumentation improvements as part of our continual improvement processes on our network of pipeline systems. As such, the attached document summarizes the status of each item and indicates that each item is now complete. We would like to take this opportunity to thank the NTSB and its staff for your thorough investigation, development of meaningful recommendations and feedback in relation to our actions to fulfill the recommendations. The efforts and improvements that Enbridge has undertaken in response to those recommendations have improved our safety management, operational reliability and continual improvement processes. These improvements better position us to accomplish our purpose and vision of supporting both a strong economy and societal lifestyle expectations by delivering energy every day in a safe and reliable manner. Should you have any questions in relation to our update please feel free to contact me directly. P-12-011: Enbridge applies continuous learning and improvement to our Integrity Management Program (“IMP”). Incorporating lessons learned and re-assessing the condition of our pipeline system has been an aspect of our IMP for many years and has been demonstrated in our responses to research output, technological advances, formalized internal review and improvement processes, regulatory audits, and investigations into non-conformances and incidents such as pipeline releases. We have addressed the recommendation to implement, as part of the excavation selection process, a safety margin that more conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections in the following manner: 1) We have modified the IMP to implement a more conservative approach in our excavation selection process in order to address uncertainities associated with the sizing of crack defects from in-line inspections (“ILI”). Specifically, Enbridge has implemented adjustments in our IMP to increase the level of conservatism as summarized below: • Utilize the lesser of nominal wall thickness or the value from an ILI tool, as input into the engineering critical assessment (“ECA”) calculation. Completed. • Enbridge no longer uses crack profile information for the depth of crack features. Instead, the maximum value of the depth bin is now being used as the starting point for crack depth estimation. Completed. • Enbridge now accounts for crack tool tolerances / uncertainty by adjusting the depth estimation by a minimum of one tool tolerance. Completed. We have addressed the recommendation to implement procedures that apply a continuous reassessment approach to immediately incorporate any new relevant information as it becomes available and reevaluate the integrity of all pipelines within the program in the following manner: 2) We created a team dedicated to a Quality Management Program (“QMP”) for integrity activities (i.e., procedures, training, audits and change management) that provides increased resources and leadership for the development and implementation of enhanced processes. Additionally, increased resources and capacity are now positioned for conducting integrity engineering assessments and strengthening of subject matter expertise related to welding, coatings, cathodic protection, repair techniques, failure models – all aspects that can support an enhanced integrity system continuous re-assessment process. Completed. 3) We implemented updated ILI data flow and quality assurance processes including formalized communication of any unreported defects that meet the detection threshold back to the ILI vendor with a documented investigation and review. Completed. 4) We integrated ILI root cause analysis of accidents into pipeline integrity programs. Completed. 5) Building upon processes already implemented, we will complete an audit and process review on the ILI vendors’ analysis processes with the objective to confirm implementation of lessons learned and to identify any additional opportunities for improvement. Completed. 6) We are preparing and implementing a Technology Improvement Plan with Enbridge ILI vendors including the incorporation of new technologies (e.g., EMAT). Completed. 7) We will conduct a comprehensive review of past Enbridge failures where ILI performance was identified as the root cause. Completed. 8) We are in the process of conducting a reliability engineering analysis of the effectiveness of hydrotesting in conjunction with ILI utilizing results from recently hydrotested Enbridge pipelines. Completed. 9) We will conduct an independent expert review of Enbridge ILI verification processes to ensure continued compliance with the new version of API 1163 expected in 2012. Completed. 10) We are reviewing current crack ILI reporting requirements and identifying opportunities to increase reporting parameters in order to improve interpretation of the results. Completed. 11) We will organize an industry review to develop the protocols for the overlay of multiple ILI data sets so as to improve integrity threat integration methods. Completed. 12) We will continue to participate and lead in industry initiatives to define standards and protocols for crack identification technology and integration of ILI data improvements. Completed. We have addressed the recommendation to develop and implement a methodology that includes local corrosion wall loss in addition to the crack depth when performing engineering assessments of crack defects coincident with areas of corrosion in the following manner: 13) We developed a methodology to ILI data overlay and assessment actions and integrated such processes into the Enbridge IMP. In particular, improvements have been made in our excavation selection criteria, crack depth estimate process, and the wall thickness value used in the crack engineering assessment. Completed. 14) Enbridge supports and leads industry efforts to improve the understanding and approach to ILI data overlay. For example, Enbridge has identified additional investigations that will support the continued development of a methodology for assessing coincidental corrosion and crack features such as organizing an industry review to develop the protocols for the overlay of multiple ILI data sets so as to improve integrity threat

Addressee Organization Type: P-Private Industry

Communication Date: 2012-12-18

Communication Type: Official Correspondence

Communication Contents: The NTSB notes that Enbridge has completed action on parts 1, 3, and 4 of this recommendation and that the company continues to address part 2, implementation of the new integrity management procedures. Pending completion of these efforts, Safety Recommendation P-12-11 is classified OPEN—ACCEPTABLE RESPONSE. The NTSB would appreciate receiving copies of Enbridge’s quality management procedures (QMP) and the new corrosion fatigue model.

Addressee Organization Type: P-Private Industry

Communication Date: 2014-11-20

Communication Type: Official Correspondence

Communication Contents: From your October 22, 2012, and January 15, 2014, letters, we learned that you had completed action on parts 1, 3, and 4 of this recommendation and that you were continuing efforts to address part 2, implementation of the new integrity management procedures. From your July 23, 2014, letter, we understood that you had continued efforts to improve your Integrity Management Program, had nearly completed action on part 2, and were in the process of conducting a reliability engineering analysis of the effectiveness of hydrotesting in conjunction with inline inspection tools using results from your recently hydrotested pipelines. We are pleased that you have completed the reliability engineering analysis and have implemented your revised integrity management procedures. Because all actions to address Recommendation P-12-11 are now complete, it is classified CLOSED—ACCEPTABLE ACTION.

Addressee Organization Type: P-Private Industry

Communication Date: 2014-03-21

Communication Type: Official Correspondence

Communication Contents: From your October 22, 2012, letter, we understood that you had completed action on parts 1, 3, and 4 of this recommendation and that you were continuing efforts to address part 2, implementation of the new integrity management procedures. We are encouraged that, since then, you have been improving your Integrity Management Program (IMP) and have implemented (1) a safety margin that more conservatively takes into account the uncertainties associated with the sizing of crack defects from in-line inspections and (2) procedures that apply a continuous reassessment approach to immediately incorporate any relevant new information as it becomes available, and that reevaluate the integrity of all pipelines within the IMP. We further understand that you are conducting a reliability engineering analysis of the effectiveness of hydrotesting in conjunction with in-line inspections using results from your recently hydrotested pipelines, expected to be completed in 2014. Pending the completion of this engineering analysis, Safety Recommendation P-12-11 is classified OPEN--ACCEPTABLE RESPONSE. As we stated in our December 18, 2012, letter, we would appreciate receiving copies of your quality management procedures (QMP) and the new corrosion fatigue model.

Addressee Organization Type: P-Private Industry

Communication Date: 2014-09-16

Communication Type: Official Correspondence

Communication Contents: From your October 22, 2012, and January 15, 2014, letters, we learned that you had completed action on parts 1, 3, and 4 of this recommendation and that you were continuing efforts to address part 2, implementation of the new integrity management procedures. We understand that, since then, you have continued efforts to improve your Integrity Management Program, have nearly completed action on part 2, and are in the process of conducting a reliability engineering analysis of the effect
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