This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

BISMARCK, N.D. — The amount of land impacted by an oil spill in North Dakota is almost 10 times larger than initially reported, officials say.

The disclosure comes about a month after the Keystone 1 Pipeline leaked about 383,040 gallons of oil.

TC Energy, the company that owns the pipeline, shut down it down Oct. 29 after discovering the oil had leaked from the pipe into the surrounding wetlands.

The pipeline was returned to service on Nov. 10 after approval by the U.S. Pipeline and Hazardous Materials Safety Administration, TC Energy said.

Initial reports of the leak released by TC Energy and North Dakota’s Department of Environmental Quality estimated about 2,500 square yards of land were affected by the spill.

Now, they have both revised the size of the impacted area to 4.8 acres, or 23,232 square yards — almost 10 times the original estimate.

The new estimate includes the surface and subsurface impact of the leak. The initial 2,500-square-yard estimate was based on visual observations alone, the company said.

“During our initial response to the incident, we immediately sectioned off a larger area (approximately 25,000 square yards) around the visibly impacted section to secure the area, provide for wildlife deterrent and air monitoring purposes,” a TC Energy representative said.

Despite this initial identification of 25,000 square yards to be blocked off, TC Energy did not update its website to reflect this number until Tuesday — after media reports of the large increase in impact estimates were released.

“This is exactly the kind of spill we are worried about when it comes to Keystone XL being built. It has never been if a pipeline breaks, but rather when,” Joye Braun, Indigenous Environmental Network frontline community organizer, said at the time of the leak.

The Department of Environmental Quality said an estimated 8,037 barrels of oil has been recovered out of the 9,120 spilled.

The Keystone 1 Pipeline system extends 2,600 miles from Alberta east into Manitoba, then south to Texas, according to TC Energy.