A U.S. probe into the rupture of an Enbridge Inc. pipeline uncovered concerns about rapid staff turnover and lack of experience among the company's Edmonton control-room staff.
The rupture in July, 2010, spilled some 20,000 barrels of crude oil into the Kalamazoo River in southwestern Michigan.
The concerns were expressed in interviews with officials of the United States National Transportation Safety Board, and contained in transcripts released by the NTSB on Friday along with other documents and photos.
Asked about staff turnover, Enbridge spokeswoman Jennifer Varey did not comment specifically on that issue, but said the company is reviewing all of the material released by the NTSB.
"We have been working co-operatively with the NTSB from the beginning, so a lot of this is not information that is new to us or new perspectives," Ms. Varey said on Monday. "But it's a lot of material newly placed in the public domain … and we are really reviewing a lot of that ourselves today."
Calgary-based Enbridge has been in the spotlight lately as it pursues the Northern Gateway project, a $5.5-billion twin pipeline project that would connect the Alberta oil sands to the West Coast and to export markets in Asia. The project has encountered stiff opposition from some native bands along the route.
Other documents released by the NTSB on Friday include details relating to the time the rupture occurred and that it went undetected as control room shifts changed.
In the transcripts, one control-room operator likens his job to that of an air traffic controller and says he'd like to see Enbridge do more to retain control-room staff in the hot Alberta job market.
"And you just don't have air traffic controllers coming in and out of the system like that, right, because you know that it will impact safety, right?" says the transcription. "So, I'd like to see them really look at keeping people in the control room, keeping us happy in there, and I don't know what it's going to take, but that's what I'd like to see."
In the same interview, the operator – coming up with his 25th year with the company – says he's seen supervisors come and go and that the cumulative experience of those doing the work has lessened over the time he's been employed.
"The day I started there [at the control centre][on]any one day you could look at the experience around the room and count a hundred years experience on four desks … now you take a look around, you know … a person with three or four years is the experienced personnel in there now."
In a statement on its website, Enbridge said that it would not comment on specific details in the documents until the NTSB completes its final report.
The company also said that it has already made changes to its operating procedures over the past two years based on its own internal investigation and will "continue to carefully examine the NTSB factual reports to determine whether any further adjustments are appropriate."
The company believes it met or exceeded all applicable regulatory and industry standards in its operations at the time of the accident, Enbridge states.
The company also said it has made several changes to "the structure and leadership of functional departments such as pipeline control, leak detection and system integrity."
According to NTSB documents, the initial and subsequent alarms associated with the rupture were not recognized as a line break "through two startup attempts and over multiple control-centre shifts."
Residents near the rupture site began calling the Marshall, Mich. 911 dispatch centre to report odours at 9:25 p.m. on Sunday; however, no calls were placed to the Enbridge control centre until 11:17 a.m. the following day. Once the Enbridge control centre was notified, nearly 17 hours after the initial rupture, remote-controlled valves were closed, bracketing the ruptured segment within a three-mile (five-kilometre) section, the documents state.
In a recent update on the Michigan spill, Enbridge said the cleanup, under the direction of the U.S. Environmental Protection Agency, has progressed to the point that a section of the Kalamazoo River is now open for recreational use.