(CNN) — A total of 210,000 gallons of oil leaked Thursday from the Keystone Pipeline in Marshall County, South Dakota, the pipeline’s operator, TransCanada, said.
Crews shut down the pipeline Thursday morning and officials are investigating the cause of the leak.
This is the largest Keystone oil spill to date in South Dakota, said Brian Walsh, a spokesman for the state’s Department of Environment and Natural Resources.
In April 2016, there was a 400-barrel release — or 16,800 gallons — with the majority of the oil cleanup completed in two months, Walsh said.
About 5,000 barrels of oil spilled Thursday.
There were no initial reports of the oil spill affecting waterways, water systems or wildlife, he said.
TransCanada said it was working with state and federal agencies.
“The safety of the public and environment are our top priorities and we will continue to provide updates as they become available,” the company said.
The sections of pipeline affected stretch from Hardisty, Alberta, to Cushing, Oklahoma, and to Wood River, Illinois, the company said.
Environmental activist group Greenpeace said the spill shows another section of the pipeline in Nebraska should not be approved.
“The Nebraska Public Service Commission needs to take a close look at this spill,” said Rachel Rye Butler of Greenpeace. “A permit approval allowing Canadian oil company TransCanada to build Keystone XL is a thumbs-up to likely spills in the future.”
The Keystone Pipeline system stretches more than 2,600 miles from Hardisty east into Manitoba and then down to Texas, according to TransCanada. The pipeline transports crude oil from Canada.
The proposed Keystone XL Pipeline, which would stretch from Hardisty down to Steele City, Nebraska, would complete the entire proposed system by cutting through Montana and South Dakota.
In March, President Donald Trump’s administration officially issued a permit that approved construction of the Keystone XL Pipeline.
The approval followed years of intense debate over the pipeline amid hefty opposition from environmental groups, who argued that the pipeline supports the extraction of crude oil from oil sands, which pumps about 17% more greenhouse gases than standard crude oil extraction. Environmentalists also opposed the pipeline because it would cut across the Ogallala Aquifer, one of the world’s largest underground deposits of fresh water.
Native American groups have argued the pipeline would cut across their sovereign lands.