(Adds context about pipeline spills, Dakota Access Pipeline, recasts throughout)
By Liz Hampton
HOUSTON, Dec 20 (Reuters) - Crews have recovered about 1,805 barrels of oil from a creek in North Dakota following a Dec. 5 spill that leaked 4,200 barrels, making it the sixth-largest pipeline leak this year, according to government data.
The cause of the spill is still not known, said Wendy Owen, spokeswoman for True Companies, which owns the Belle Fourche Pipeline. Of the total spill, about 3,100 barrels leaked into the nearby Ash Coulee Creek, a small waterway that feeds the Little Missouri River, a tributary of the Missouri River.
The spill has been contained. Last week, she noted that pipeline equipment did not detect the spill, possibly because the 2,400 barrel-per-day line runs intermittently.
The leak occurred just 150 miles from the site of protests against the Dakota Access Pipeline, a crude line whose planned route was under the Missouri River. The Little Missouri feeds the main river upstream of the Dakota Pipeline crossing.
The spill happened as pipeline companies such as Energy Transfer Partners, which saw the Dakota Access halted in December by the U.S. government, are trying to convince critics that their systems are the safest way to move crude and other products.
The incident underscores concerns of the Standing Rock Sioux Tribe, whose land is adjacent to the planned pipeline route, and others who have said that a leak from the Dakota Access could contaminate drinking water or desecrate sacred lands.
So far, the total number of hazardous liquids pipeline spills in 2016 is on track to fall short of 2015. As of Nov. 30, there were 354 spills, versus 462 for all of in 2015, according to data from the Pipeline and Hazardous Materials Safety Administration (PHMSA).
However, the percentage of spills releasing larger volumes of liquids has been higher this year, the data shows.
About 16 percent of pipeline releases in 2016 involved 100 or more barrels of product, versus about 13 percent last year. The percentage involving 1,000 barrels or more has been slightly higher as well for 2016, at 3.4 percent, versus 3 percent last year.
The two largest leaks this year have involved crude pipelines. In September, Sunoco Logistics, the operator of the Dakota Access, spilled 8,600 barrels of oil from its Permian Express II pipeline near Sweetwater, Texas. The company had previously been fined for violating welding practices on that line.
In October, Enterprise Products Partners released over 7,600 barrels of oil from its Seaway Crude pipeline near Cushing, Oklahoma.
Belle Fourche reported a 1,958 barrel leak of refined products on its system in Campbell County, Wyoming in 2011, and less than a month later suffered a 1,000 barrel spill of crude oil on its line near McKenzie, North Dakota. (Reporting by Liz Hampton; Editing by Alistair Bell)