Another major incident investigation finds serious cultural failures, poor training for operators and emergenjcy responders, poor emergency planing, and technical failures in the Mechanical Integrity program.   The crude oil pipeline company's pervasive organizational failures caused a massive 2010 spill in Michigan, an National Transportation Safety Board (NTSB) preliminary investigation has found. The investigation found that multiple small corrosion fatigue cracks grew in size and linked together (MI inspection failures), causing a breach more than 80 in. long in the pipeline on July 25, 2010.

NTSB has said it identified a complete safety breakdown resulting in the discharge of more than 840,000 gal of crude into Talmadge Creek and the nearby Kalamazoo River for 17 hr until a local utility worker discovered the spill and notified Enbridge. Operators failed to recognize the pipeline had ruptured and continued to pump crude into the environment. Despite multiple alarms and a loss of pressure in the pipeline, operators failed to follow their own shutdown procedures through three shifts.

The board’s draft finding came after the US Pipeline and Hazardous Materials Safety Administration proposed a record $3.7 million fine and 24 enforcement actions against Enbridge on July 2 in connection with the incident.

Conclusions

1. The following were NOT factors in this accident: 
   1. cathodic protection, 
   2. microbial corrosion, 
   3. internal corrosion, 
   4. transportation-induced metal fatigue, 
   5. third-party damage, and 
   6. pipe manufacturing defects 
2. Insufficient information was available from the postaccident alcohol testing; however, the postaccident drug testing showed that use of illegal drugs was NOT a factor in the accident.
3. Had the firefighters discovered the ruptured segment of Line 6B and called Enbridge, the two startups of the pipeline might not have occurred and the additional volume might not have been pumped.
4. The Line 6B segment ruptured under normal operating pressure due to corrosion fatigue cracks that grew and coalesced from multiple stress corrosion cracks, which had initiated in areas of external of corrosion beneath the disbonded polyethylene tape coating.
5. Title 49 Code of Federal Regulations 195.452(h) does not provide clear requirements regarding when to repair and when to remediate pipeline defects and inadequately defines the requirements for assessing the effect on pipeline integrity when either crack defects or cracks and corrosion are simultaneously present in the pipeline.
6. The Pipeline and Hazardous Materials Safety Administration (PHMSA) failed to pursue findings from previous inspections and did not require Enbridge Incorporated (Enbridge) to excavate pipe segments with injurious crack defects.
7. Enbridge's delayed reporting of the "discovery of condition" by more than 460 days indicates that Enbridge's interpretation of the current regulation delayed the repair of the pipeline.
8. Enbridge's integrity management program was inadequate because it did not consider the following:
   1. a sufficient margin of safety,
   2. appropriate wall thickness,
   3. tool tolerances,
   4. use of a continuous reassessment approach to incorporate lessons learned,
   5. the effects of corrosion on crack depth sizing, and
   6. accelerated crack growth rates due to corrosion fatigue on corroded pipe with a failed coating.
9. To improve pipeline safety, a uniform and systematic approach in evaluating data for various types of in-line inspection tools is necessary to determine the effect of the interaction of various threats to a pipeline.
10. Pipeline operators should not wait until PHMSA promulgates revisions to 49 Code of Federal Regulations 195.452 before taking action to improve pipeline safety.
11. PII Pipeline Solutions' analysis of the 2005 in-line inspection data for the Line 6B segment that ruptured mischaracterized crack defects, which resulted in Enbridge not evaluating them as crack-field defects.
12. The ineffective performance of control center staff led them to misinterpret the rupture as a column separation, which led them to attempt two subsequent startups of the line.
13. Enbridge failed to train control center staff in team performance, thereby inadequately preparing the control center staff to perform effectively as a team when effective team performance was most needed.
14. Enbridge failed to ensure that all control center staff had adequate knowledge, skills, and abilities to recognize and address pipeline leaks, and their limited exposure to meaningful leak recognition training diminished their ability to correctly identify the cause of the Material Balance System (MBS) alarms.
15. The Enbridge control center and MBS procedures for leak detection alarms and identification did not fully address the potential for leaks during shutdown and startup, and Enbridge management did not prohibit control center staff from using unapproved procedures.
16. Enbridge's control center staff placed a greater emphasis on the MBS analyst's flawed interpretation of the leak detection system's alarms than it did on reliable indications of a leak, such as zero pressure, despite known limitations of the leak detection system.
17. Enbridge control center staff misinterpreted the absence of external notifications as evidence that Line 6B had not ruptured.
18. Although Enbridge had procedures that required a pipeline shutdown after 10 minutes of uncertain operational status, Enbridge control center staff had developed a culture that accepted not adhering to the procedures.
19. Enbridge's review of its public awareness program was ineffective in identifying and correcting deficiencies.
20. Had Enbridge operated an effective public awareness program, local emergency response agencies would have been better prepared to respond to early indications of the rupture and may have been able to locate the crude oil and notify Enbridge before control center staff tried to start the line.
21. Although Enbridge quickly isolated the ruptured segment of Line 6B after receiving a telephone call about the release, Enbridge's emergency response actions during the initial hours following the release were not sufficiently focused on source control and demonstrated a lack of awareness and training in the use of effective containment methods.
22. Had Enbridge implemented effective oil containment measures for fast-flowing waters, the amount of oil that reached Talmadge Creek and the Kalamazoo River could have been reduced.
23. PHMSA's regulatory requirements for response capability planning do not ensure a high level of preparedness equivalent to the more stringent requirements of the U.S. Coast Guard and the U.S. Environmental Protection Agency.
24. Without specific Federal spill response preparedness standards, pipeline operators do not have response planning guidance for a worst-case discharge.
25. The Enbridge facility response plan did not identify and ensure sufficient resources were available for the response to the pipeline release in this accident.
26. If PHMSA had dedicated the resources necessary and conducted a thorough review of the Enbridge facility response plan, it would have disapproved the plan because it did not adequately provide for response to a worst-case discharge.
27. Enbridge's failure to exercise effective oversight of pipeline integrity and control center operations, implement an effective public awareness program, and implement an adequate postaccident response were organizational failures that resulted in the accident and increased its severity.
28. Pipeline safety would be enhanced if pipeline companies implemented safety management systems.

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:

1. Deficient integrity management procedures, which allowed well-documented crack defects in corroded areas to propagate until the pipeline failed.
2. Inadequate training of control center personnel, which allowed the rupture to remain undetected for 17 hours and through two startups of the pipeline.
3. 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.

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