As teams continue to clean stained vegetation and retrieve pooled oil from the Yellowstone River, the state is questioning ExxonMobil’s data.
Department of Environmental Quality Director Richard Opper sent a letter to ExxonMobil’s CEO Rex Tillerson on Monday, demanding an explanation from the company about how much oil spilled into the river.
ExxonMobil initially reported that a break in a pipeline under the river on July 1 caused between 31,500 and 42,000 gallons of crude oil to spill into the river after the 12-inch pipe failed at 10:40 p.m.
The line was shut down seven minutes later, but the flow of oil didn’t completely stop until 11:36 p.m., according to Exxon.
ExxonMobil initially said the leak was stopped within six minutes.
Opper’s letter takes issue with the amount of oil that Exxon reported spilled into the river.
“Since the event occurred, ExxonMobil has increased its estimate of the duration of the spill event 10-fold from its original assertion of six minutes. Despite this revision as to the duration of the event, ExxonMobil has not revised its estimate as to the volume of oil spilled into the river from the company’s original projection...”
“In addition to the flow and pressure data requested above, we request an explanation as to how ExxonMobil arrived at, and why ExxonMobil has not revised, its estimate of the volume of oil spilled into the Yellowstone River,” Opper said in the letter.
Opper demanded more details from Exxon as soon as possible, but no later than July 18.
The letter was also sent to the state attorney general, the governor and the state’s chief legal counsel.
ExxonMobil officials said Wednesday that they are standing by the volume estimate of 750 to 1,000 barrels of spilled oil.
"The estimate includes oil lost during the total duration of the incident," said media relations adviser Cynthia Bergman White in an e-mail Wednesday.
Bergman White added that while power to the pumps was shut off in six minutes, the pump mechanism continued to decrease pressure for a short while after.
"We used a more conservative, eight minutes to calculate the oil that escaped under pump pressure during that period of time," Bergman white said.
She said Exxon will be providing Gov. Brian Schweitzer and officials at the Montana Department of Environmental Quality with the basis of the calculations.
On Tuesday, Exxon representatives and state and federal agencies provided an update to city and county staff on the cleanup effort.
Mike Petronis of the U.S. Department of Transportation said he inspected the pipeline just weeks before it ruptured. At that time, Petronis said it met all federal standards.
“The line is buried, so I don’t look at the line, I look at records, talk to personnel and make sure they are meeting federal guidelines and meet code,” Petronis said during the noon gathering at the Yellowstone County Courthouse.
During that inspection, Petronis said he was more concerned by the southern bank of the Yellowstone River along Riverside Park in Laurel than he was about the pipeline.
“If it failed, the pipeline was shallower through the park,” Petronis said. “If the river rerouted through the park and over the pipeline, becoming exposed, we’d have a problem.”
Instead, the 12-inch wide, half-inch thick section of 20-year-old pipe covered in several inches of concrete coating burst.
Tom Livers, department director of the Montana Department of Environmental Quality, said representatives from the California Department of Environmental Quality are in Billings to assist in the pipeline investigation.
“We will get a truly independent look at this,” Livers said. “They have experience and we don’t. This is our first time, but I hope it’s our last.”
Geoff Craft of ExxonMobil said the ruptured pipe will not be repaired. Instead, it will be replaced.
Craft said a permit meeting was being held on Wednesday with about six permitting offices.
“The time frame for the drill depends on the permit meeting,” Craft said. “It takes three to four weeks from the time we fire the gun and say go.”
The refinery has been operating at minimum rate, trucking in crude oil. ExxonMobil officials said they are making sure the refinery continues to provide gas and diesel fuel for Montana, keeping the refinery’s 250 workers on the job.
Since the spill, Steven Merritt with the Environmental Protection Agency said cleanup crews have recovered 942 barrels of oily liquids. About nine of those barrels are oil.
They have also collected more than 500 cubic yards of oily plants, cleaned using 40,000 linear feet of absorbent booms and 8,600 square feet of absorbent pads.
Crews began testing sediment Monday, retrieving between 40 and 50 samples so far.
Jeff Miller and Alex Mahrou were out along the river off Thiel Road on Tuesday afternoon taking some samples.
“We focus on the slow-moving parts of the river or backwaters, places that have been affected by the oil spill,” said Miller, of URS Operating Services.
They collected six samples on Tuesday using a sediment auger. The samples were put on ice and sent out for testing.
Other workers are continuing to retrieve recoverable oil, shifting more focus on cleaning and removing oiled vegetation.