A Montana pipeline that spilled 30,000 gallons of oil had been split at the site of an exposed weld where the line crosses beneath the Yellowstone River, officials said, prompting a warning for pipeline companies nationwide to take precautions against flooding.
The damaged section of the 12-inch pipeline that crosses the Yellowstone upstream of the city of Glendive was pulled from the river Wednesday.
It will be sent to a laboratory in Oklahoma for analysis, said Tim Butters, pipeline safety administrator at the U.S. Department of Transportation. The cause of the split has not been determined.
"There are a number of different scenarios," Butters said in a telephone interview with The Associated Press. "Was it metal-related? Was it external force related? All of that needs to be looked at."
The Yellowstone spill in January contaminated water supplies for about 6,000 residents of Glendive and raised public health concerns in communities downstream in North Dakota.
The line, which was installed in 1967, is owned by Bridger Pipeline LLC of Casper, Wyoming. Company spokesman Bill Salvin said the break occurred along a section of the line between 100- and 120-feet long that somehow became exposed to the river.
An advisory warning pipeline companies about potential damage from severe flooding was scheduled to be published Thursday in the Federal Register. It cites the recent Yellowstone spill and several prior pipeline accidents caused by flooding or similar issues at river crossings in Iowa, Nebraska and Montana.
There are thousands of such river crossings nationwide, including at least 64 in Montana.
Federal regulations require pipelines to be buried just four feet beneath river bottoms.
Officials have said they have no plans to tighten those rules. Rather, it's up to companies to make sure their pipelines are safe, Butters said.
Only about 2,500 gallons of oil were recovered from the January spill.
Salvin said Bridger Pipeline will begin assessing the river's shoreline for damage once water levels drop. However, no more oil is expected to be recovered.
"We've recovered everything that can be recovered at this point, so it's now what can be remediated," he said.