CALGARY, Alberta, April 8 (UPI) -- Pipeline company TransCanada said about 400 barrels of oil leaked near the Keystone pipeline in South Dakota, far more than the company originally estimated. 
 
 The company started the process of closing down its Keystone oil pipeline after discovering oil released Saturday near a pump station in South Dakota. Initial estimates put the size of the release at about 125 barrels. 
 
 "We have completed our initial modeling and have provided to regulators an estimate of the potential volume of 400 barrels," the company said in an emailed statement. 
 
 The company maintained there were no threats from the release to the environment or to public health. A spokesperson said Monday the size of visible oil at the sight covered about 300 square feet. No response was offered when asked by UPI to address the revision to the size of the release. 
 
 The company said it based its estimate on the soil excavated to expose more than 100 feet of the pipeline. More than 100 workers were on site to assess the situation alongside members of the federal Pipeline and Hazardous Materials Administration. 
 
 TransCanada had a permit to build Keystone XL, an extension to the original pipeline, denied by the U.S. government in part on environmental grounds. Early critics of the project pointed to a history of breaks along the current route and raised concerns about the potential harmful environmental impact of heavy crude oil from Alberta. 
 
 The Keystone oil pipeline will remain closed while TransCanada examines the situation in South Dakota. The pipeline runs from Alberta, Canada, to terminals in Cushing, Okla., and Wood River, Ill. That section is directly impacted by the release, though consumers linked to a line stretching from Cushing to the U.S. Gulf Coast remain supplied. ||||| SOUTH DAKOTA (NEWS10) – The Keystone Pipeline leak is apparently worse than first thought. 
 
 TransCanada Corporation now says it appears approximately 16,800 gallons of oil have leaked in South Dakota since Saturday. The company says it reported the 400-barrel estimate Thursday to the National Response Centre and the Pipeline and Hazardous Materials Administration. It says the estimate is based on the excavation of soil to expose more than 100 feet of pipe and takes into account factors including oil observed in the soil and the potential area affected. 
 
 At first officials said less than 200 gallons were spilled. 
 
 TransCanada says the leak has been “controlled” although they have yet to find the source of the leak. The company has told customers the pipeline will remain closed until early next week. 
 
 The pipeline runs from Alberta, Canada, to refineries in Illinois and Cushing, Oklahoma, passing through the eastern Dakotas, Nebraska, Kansas and Missouri. The Keystone pipeline can handle 550,000 barrels, or about 23 million gallons, daily. It’s part of a pipeline system that also would have included the Keystone XL pipeline had President Barack Obama not rejected that project last November. 
 
 Analysts say the shutdown will have a short-term impact in which less-heavy Canadian crude will be getting to the market, but the system is already oversupplied so consumers are unlikely to see an impact at the pump.
– The Keystone pipeline sprung a leak Saturday, and TransCanada was slightly off in its original estimate of how much oil spilled into Hutchinson County, South Dakota—by about 9,000% or so. CNN reports the oil company originally estimated that only about 187 gallons had spilled. On Thursday, it updated that estimate to about 16,800 gallons after excavating more than 100 feet of pipe, News 10 ABC reports. While TransCanada has yet to find the source of the leak, it says it's been "controlled" by shutting off a section of the pipeline. CNN quotes TransCanada as stating it hasn't "observed significant impacts to the environment" from the leak. The company claims the leak poses no threat to public health, UPI reports. The affected section of the Keystone pipeline will remain closed until early next week while workers search for the leak. While less oil will be entering the US market from Canada for the time being, analysts say consumers won't be affected as there is currently more than enough oil available. Last November, President Obama vetoed an extension of the Keystone pipeline known as Keystone XL at least partly due to environmental concerns. TransCanada is currently challenging that veto in federal court. CNN quotes the executive director of the Sierra Club as saying the current leak in South Dakota "is a stark reminder that it's not a question if a pipeline will malfunction, but rather a question of when."