by Alejandro Davila Fragoso CLIMATE PROGRESS

CREDIT: AP Photo/Nati Harnik

Nearly a week after pipeline operator TransCanada shut down a section of its Keystone line over an oil leak, the company reported Thursday thousands of gallons of oil were spilled, not less than 200 as it first said.

Based on soil excavations, TransCanada said about 16,800 gallons of oil leaked onto a field in South Dakota, the Associated Press reported. After the leak was discovered Saturday and the line was shut, TransCanada said about 187 gallons of crude oil had spilled, an accident that environmental groups said shows the dangers of shipping oil by pipeline. Though the spill is larger than first thought, it poses no significant environmental effects or threats to public safety, the AP said. However, Keystone transports Canadian tar sands oil, which is more difficult to clean than conventional oil.

The company behind the rejected Keystone XL line has yet to reveal what caused the leak, but it said the spill is being controlled, and reported the new estimates to the National Response Center and the Pipeline and Hazardous Materials Administration. The pipeline is part of the existing Keystone network that the proposed Keystone XL pipeline would have expanded. It runs from Alberta, Canada, to refineries in Illinois and Oklahoma via the Dakotas, Nebraska, Kansas, and Missouri. TransCanada said the pipeline won’t be fully operational until early next week. So far some 100 workers are at the site, located about four miles from Hutchinson County.

Misreported leak volumes often occur following oil spills as companies investigate accidents and discover oil seeped deeper in the ground or waterways than they first thought. Revised figures are at times much larger than first reported. In 2014, for instance, an oil spill in North Dakota was first reported to have caused a loss of 750 barrels of oil, a figure that climbed to about 20,600 barrels once the soil was further investigated.

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After the spill was reported earlier this week, environmental groups said Keystone’s spill proves the threat that the Keystone XL expansion would have posed. They also noted that the Keystone pipeline, approved by President George W. Bush in 2008, leaked oil 12 times in its first year of operation. “TransCanada’s Keystone I disaster is a stark reminder that it’s not a question if a pipeline will malfunction, but rather a question of when. This is one of the reasons President Obama rejected the Keystone XL pipeline and it’s why he should reject all dangerous fossil fuel pipeline proposals,” Sierra Club’s Executive Director Michael Brune said in a statement.

Oil transportation largely relies on trains and pipelines. Out of those two, pipelines spill more often than trains, yet train accidents can be deadlier as trains are more likely to explode. U.S. pipelines spilled three times as much crude oil as trains over the period of 2004 to 2012, according to an International Energy Agency study. And last year, the Pipeline and Hazardous Materials Safety Administration reported 314 “significant” incidents causing damages of more than $305 million, and 10 fatalities.

Despite opposition from environmentalists and mounting leaks, TransCanada is determined to expand its system and refuses to shelve Keystone XL, as it has challenged Obama’s decision under the North American Free Trade Agreement in federal U.S. court.