NTSB findings on Enbridge Kalamazoo spill

Almost exactly 2 years ago there was a massive spill of crude oil from an Enbridge pipeline in Michigan.  Ultimately about 3 ML of oil (a good couple of Olympic pools) was released and entered the Kalamazoo River, with short-term health effects on about 300 local residents plus extensive environmental damage that is still continuing.  The oil did not ignite but in every other sense this was a very serious pipeline failure.

The US National Transportation Safety Board yesterday released its conclusions and recommendations on this failure (press release and report synopsis).  The Board is scathing about Enbridge actions in both the lead-up to the spill and the response once it occurred.  I find it particularly interesting that the opening words in the NTSB press release are “Pervasive organisational failures …”.  This yet again reinforces that in technological systems the ultimate causes of failures are human and organisational and not purely technical.

In this case the immediate cause of the failure was stress corrosion cracking.  SCC is a known problem in many pipelines, with known consequences and known methods of monitoring and management.  However the NTSB says Enbridge failed to monitor SCC adequately and misinterpreted the data that they obtained – organisational failures at several levels.  Then when the pipeline ruptured it took the Enbridge control room 17 hours, including two attempted restarts and multiple breaches of their own procedures, to realise that the oil they were continuing to push into the line was not being delivered to its destination but was being pumped into the environment – more organisational failures.  There were also significant regulatory failures.

The message of the Andrew Hopkins and Energy Pipelines CRC Research Program 4 on the sociology of safety needs to be spread far and wide, if only those who need to know could be persuaded to listen.

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5 Responses to NTSB findings on Enbridge Kalamazoo spill

  1. Adrian Amey says:

    Hi Peter

    I think a sound argument can be made that any failure resulting from a foreseeable threat is a organisational failure in that the licensee (as an organisation) failed to prevent a forseable failure.

    Of couse it could also be argued that regulators (as an organisation) failed to ensure the licensee organisation prevented the foreseeable failure.

    Everyone should consider themselves responsible for the safety of the pipeline – licensees, regulators, consultants and contractors.


    • petertuft says:

      Agree completely – it seems obvious doesn’t it? Trouble is there are still people and organisations of all types who don’t see the obvious, as illustrated by both this failure and the San Bruno disaster among others.

  2. petertuft says:

    Phil Venton sent the following comment to me directly and it seems worth copying here (with a couple of minor adjustments):

    A couple of technical observations that are pertinent (numerical references to the NTSB findings):

    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.

    PBV: This is interesting – unlike gas lines, liquid lines undergo large stress ranges between operating and shutdown conditions – and fatigue, particularly if there is an initiator is a real consideration. People usually set the SCC risk for liquids lines as low, but clearly that is not the case here. There was stress, stress range, tape coating. the only missing item was probably temperature – so the operator should have had a concern for SCC.

    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.

    PBV: I guess in 2005 PII’s capability to detect cracks was just being proven. It does not state whether the tool that was run had the capability to detect cracks (usually UT, not MFL, and in the future maybe EMAT) – this may not be a problem for future inspections, but shows that it is important to know enough about the deterioration mechanism to select the correct tool.

    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.

    PBV – the report said the pipeline was in a shutdown – it appears that there must be an elevation difference and they thought there was slack flow – suggests limited knowledge of system operation.

    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.

    PBV – a frequent problem in a system that has poorly implemented MBS. I recall a particular pipeline where they reckoned their system would identify a fairly small MBS error because the system modelled the pipeline hydraulics, compressibility and so on – in addition to the MBS a pipeline pressure profile trend (predicted vs measured) is useful in detecting leaks – presuming that the SCADA monitored pressures at useful intervals.

  3. Peter Owbridge says:

    Would concur with all of the above comments and still grapple with the attached article from the Techcorr Energy Newswire regarding the fact that despite horrendous costs in clean up, fines etc, the impact on the bottom line is minimal. Lets hope the soiciology angle will prove more worthwhile. I attach a snippet and the link to the full article:

    “Cleaning up the Kalamazoo River, which reopened for human use this month, would have cost Enbridge $765 million US (almost 70 per cent of its 2011 profit), but insurance covered $650 million of that. The loss of $115 million works out to more than $5,700 for each spilled barrel – more than a flea bite, certainly, but not a disastrous loss for a company with a market capitalization of $31 billion.
    A graph showing the Enbridge stock price after the financial crisis of 2008 climbs gradually upward with no noticeable divot during the summer of 2010, when the spill took place.”

  4. petertuft says:

    The monetary costs of failure almost always seem insignificant. The M$3.7 fine proposed for Enbridge is almost laughable – it would be a lot or money if it came out of my pocket but it’s only about 0.01% of the market capitalisation or 0.3% of annual profit. It does seem likely that they will be paying a lot more in insurance premiums though, and that might be more of an incentive to improve.

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