TransCanada’s Bison pipeline has resumed normal operations and is providing valuable lessons for safety and integrity after experiencing a failure in July 2011.
Pipelines are by far the safest and most efficient way of transporting oil and natural gas to power our daily lives. Thankfully, the thousands of miles of energy pipelines that criss-cross the United States do just that every day. For the vast majority of people, they are out of sight and out of mind as they safely and reliably deliver the fuel we need to move our vehicles, heat our homes and generate our electricity.But like any technology, pipelines are not perfect. Problems do arise from time to time, and the very rare instances when pipelines leak are justifiably cause for public concern. Responsible companies recognize this and invest heavily in systems to prevent failures from occurring in the first place and preparing to respond quickly if they do.
That’s exactly what TransCanada has done in the case of our Bison natural gas pipeline, which failed on July 20, 2011 near Gillette, Wyoming. Thankfully, there were no injuries or property damaged as a result of this line break, and all of the safety mechanisms on the pipeline and in our control center worked as they were designed to, shutting down the flow of gas within minutes.
The Bison pipeline returned to service in late July 2011 and has been operating without any safety incidents since that time. Since then, TransCanada has completed a thorough investigation into the incident in conjunction with the Pipelines and Hazardous Materials Safety Administration (PHMSA) to ensure the pipeline continues to live up to our company’s industry-leading safety record. These efforts have resulted in PHMSA closing out its corrective action order on the Bison pipeline on November 8 – a relatively short timeframe for an order of this nature to be resolved.
The investigation determined that the quality of our pipeline materials and welding were not factors. So how did the failure occur? One of the leading causes of pipeline breaks are third parties hitting the line by mistake (hence the importance of calling 811 before you dig), but in this case we determined that the pipe most likely suffered damage while it was being buried at the end of construction. This resulting defect is suspected to have grown during our routine post- construction pressure test and normal operation of the pipeline, eventually leading to failure on the evening of July 20.
Experts who have reviewed this case agree that it was a highly unusual situation that would have been difficult to predict. I am glad to say that the work we have put into identifying this cause now gives us a much better idea of what to look for during our regular pipeline inspections so that we can catch these small defects before they become big problems in the future.
Pipeline failures can impact communities, are incredibly costly and damaging to the operator’s reputation. That’s why it’s in our own interest to prevent failures from happening and to minimize the impacts of any problems that do happen. We work to learn everything we can from these rare events and then apply what we have learned to our other facilities in order to make them even safer. TransCanada invests $200 to $300 million each year in inspecting, repairing and upgrading our pipeline systems.
As North America’s largest natural gas transporter, TransCanada has more than 60 years’ experience building and operating safe and reliable pipelines. Problems with our facilities are rare, but we are committed to addressing them quickly and completely because the safety of our employees and the general public is always our top priority.