The night of July 1, 2011 “was a usual night, not too busy and not overly slow” at ExxonMobil’s pipeline control facility in Houston, Texas. A controller at the Houston facility was operating pipeline controls at his new workstation, known as "console 2." This controller had recently been trained on this console, and had been operating it singlehandedly for only a month. Little did he know that, over 1,500 miles away, massive flooding was about to blow a leak in one of the pipelines under his watch.
The story of that July night, and of the controller's experience, comes from a report released in early January by the Pipeline and Hazardous Materials Safety Administration (PHMSA). The report investigates in detail the cause of what happened later that July 1 evening, when the Silver Tip pipeline near Laurel, Mont., ruptured in the middle of the violently flooding Yellowstone River, releasing 1,500 barrels of oil over the course of nearly an hour. The investigation is also part of an effort to take a critical look at existing pipeline regulations. The Yellowstone spill has prompted a nationwide survey of the nation’s pipelines, and has also stirred up talk about changing pipeline regulations.
One thing the report makes clear is that pipeline damage from flooding was a major concern prior to the 2011 spill. That’s because the Yellowstone River had busted pipelines before. On June 7, 2009, an eight-inch natural gas line was exposed as the swollen river scoured the riverbottom. The line broke under the river’s force, releasing gas “for a few hours” before the valves were shut off, according to the report.
The year after the gas line break, the town leaders in Laurel called a summertime meeting at its Riverside Park. The Army Corps of Engineers, ExxonMobil Pipeline Company, and the handful of other pipeline companies operating in the area were called in to see for themselves the erosion taking place on the riverbank. The city “was hoping one of the entities would assist in the fortification of the south bank,” reads the report, but that didn’t happen.
A whole string of meetings and correspondence followed. In October 2010, at the urging of Laurel officials, PHMSA contacted pipeline operators, focusing on the ExxonMobil pipeline because its line carried oil. ExxonMobil agreed to inspect its pipeline at the river crossing, and the line checked out okay: the pipe was covered by a minimum of five feet of riverbed -- more than the four feet mandated by federal regulations.
Then, in May 2011, as heavy spring rains swelled the river, PHMSA again contacted ExxonMobil at the city’s request. The company shut down their pipeline for five hours to assess the situation, but turned it back on with the agreement that they’d do a “daily drive-by” to check on the south bank. The river was too violent, the pipeline safety administration said, to inspect the pipeline itself.
On May 31, because of fears about flooding, PHMSA began coordinating with all pipeline operators in the state. The rains were letting up, but the summer snowmelt had barely begun. The ExxonMobil pipeline continued to be a matter of concern during the events leading up to the pipeline’s failure, as this timeline of events from the report shows:
June 1: “City of Laurel e-mailed ExxonMobil photos of Yellowstone River. City of Laurel personnel recommended that ExxonMobil staff again come to Laurel to assess the situation.”
June 6, 2011: PHMSA “conducted an inspection of ExxonMobil’s . . . management program on the Silvertip Pipeline.”
June 24, 2011: “the City of Laurel again expressed concern to PHMSA (western region) staff over the ExxonMobil pipeline.”
Then, at 10:41PM on July 1, that Houston-based ExxonMobil controller, sitting at console 2, got the alarm that pressure had dropped at the main pump about fifteen miles south of Laurel. The pump, sensing the pressure drop which could signal a leak, had automatically shut itself down.
Since the controller “believed that he might have a leak,” he started shutting down other pumps and valves too, first at the head of the line, in Wyoming, then near the refinery in Laurel. This sequence took about 10 minutes, enough time for 381 gallons of crude oil to spill into the river.
The controller also called in his supervisor, who called the field supervisor in Montana at 11:10PM, who in turn called a senior technician. The technician talked to the Houston supervisor, and they had a lengthy conversation about what could be causing the loss of pressure in the pipeline.
Then, the Houston supervisor noticed that the first alarm had actually been a pressure drop at the valve immediately upstream of the Yellowstone River. He shut the valve.
The problem was, 46 minutes had passed. During that time, more than sixty miles of twelve-inch pipeline, sloping 5-7 percent downhill, had drained another 1100 barrels of crude into the river.
The report says that the Houston supervisor was proud of the way the controller handled the situation. But it goes on to highlight concerns about the lack of information available to employees in the Texas control center: “The Controller was generally aware that there had been some flooding in Montana,” reads the report, “but there was no specific notification required nor was there any contingency training in anticipation of possible problems to be encountered from excessive flooding.”
The release of the report also signals an effort to take a critical look at regulations in the wake of the 2011 spill. A January 2012 law introduced by Montana Senators Max Baucus and Jon Tester required PHMSA to conduct a study of other pipeline spills on waterways. According to the study, between 1991 and 2009, there were thirteen “significant” incidents at inland water crossings around the country.
The Billings Gazette, in a recent opinion piece, criticized the slow pace of action since the spill.
But according to Damon Hill, a pipeline safety administration spokesman, “the study was just a start.”
Marshall Swearingen is a High Country News intern.
Image courtesy US Fish and Wildlife Service via Flickr Creative Commons.