One month after a 65-year-old ExxonMobil pipeline burst without warning and dumped Canadian tar sands oil in the town of Mayflower, Ark., government investigators and residents are still looking for answers to basic questions about the spill.
When did the pipeline begin leaking? When and how did the oil company find out about it? How quickly did the company act? How much oil spilled from the pipeline's 22-foot-long gash? And what condition was the line in before it ruptured?
The unanswered questions are urgent because they speak to issues of pipeline safety and enforcement as thousands of miles of new and reconfigured pipelines—including the Keystone XL—are being proposed to run across the United States.
Three groups are currently investigating the Mayflower spill. The Pipeline and Hazardous Materials Safety Administration (PHMSA), a branch of the Department of Transportation that is primarily responsible for developing and enforcing pipeline regulations, is handling the official federal inquiry into the cause of the pipeline rupture. Arkansas Attorney General Dustin McDaniel has launched his own investigation into the spill and is reviewing more than 12,500 pages of documents that Exxon turned over at his request. U.S. Representative Ed Markey (D-Mass.) is also doing his own inquiry of the spill.
Last week InsideClimate News sent transcripts of the 911 police reports it obtained from the Faulkner County Sheriff's Office to Rep. Markey's office upon its request. The transcripts are also being released publicly here.
They tell a different story than what Exxon reported to the federal government in the initial days of the spill, which was also different from what the company told the public in subsequent weeks.
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Below is a summary of the most pressing unanswered questions and inconsistencies. All times have been converted to local time (CDT).
When did the Pegasus pipeline start leaking, and when did Exxon find out about it?
Police records show that Mayflower resident Jennifer Dement of 50 Starlite Road North was the first to report the oil spill to local law enforcement at 2:44 p.m. on March 29. But when the pipeline ruptured, and how long it took Exxon to discover the leak, are still unclear. In the four weeks since the spill, the company has given four different answers to these questions.
In the initial incident report the company filed with the National Response Center on the day of the spill, Larry Hawthorne, an Exxon field regulatory specialist, said Exxon's command center in Houston detected a drop in pressure on the line at 1:15 p.m. In a second NRC report filed by a different Exxon employee later that day, the time of discovery was listed as 3:20 p.m. In a third and final report, it was changed back to 1:15 p.m.
To add to the confusion, Hawthorne told InsideClimate News in an interview on April 10 that Exxon confirmed the spill when company representatives arrived on the scene at 3:15 p.m., and that any mention of an earlier detection time was a mistake by the NRC. But police transcripts don't place Exxon representatives at the spill site until 3:43 p.m.
An NRC official checked the audio recordings of Exxon's emergency calls for InsideClimate News and confirmed the accuracy of the incident reports.
Most recently, in an April 10 post on the company's blog, ExxonMobil's Perspectives, Exxon's vice president of public and government affairs, Ken Cohen, said it first detected a pressure drop in the line at 2:37 p.m.
How did Exxon find out about the spill?
According to Exxon's account on its blog, a low pressure alarm was received at 2:37 p.m. at ExxonMobil Pipeline Company's Operations Control Center in Houston.