An investigation is underway after an Enbridge pipeline leaked crude oil into a field in Wisconsin.

Officials say the pipeline was shut down within minutes of the leak, which spilled about 1,200 barrels of oil near Grand Marsh, Wisconsin on Friday. 

"Our control centre detected a pressure drop on Line 14 which runs through Wisconsin in the United States. The operator shut down and isolated the line very quickly, within 5 minutes," Graham White, an Enbridge spokesperson, tells CTV News.

"Shortly thereafter we did receive a call from a resident confirming there had been a release near the site near a town called Grand Marsh."

White says inspectors and cleanup crews were quickly dispatched to the area and were able to contain the spill, which occurred in a rural field.

"It appears to mostly be on the surface," White said.

There appears to be some oil on two small farm ponds located near the leak but White says the ponds are not located near moving waterways.

"There is no flowing water here, there's no river or streams."

No injuries have been reported and it appears only one landowner may be affected.

On Saturday, U.S. officials confirmed an investigation was underway.

“I can confirm that Enbridge Energy Partners experienced a leak on their Line 14 pipeline in Adams County, Wisconsin. The Pipeline and Hazardous Materials Safety Administration has authority over this operator and has sent inspectors to the site to conduct a failure investigation,” said Damon Hill, a spokesman for the U.S. Department of Transport.

“The Environmental Protection Agency is on the on-scene coordinator.”

White confirms regulatory agencies including The Pipeline and Hazardous Materials Safety Administration, the Wisconsin Department of Natural Resources and the Environmental Protection Agency are on site and an investigation has begun to determine what caused the leak.

The affected line has a capacity to transport 317,600 barrels per day to Chicago-area refineries.

White said other lines are being used to compensate deliveries to those refineries as the particular line which leaked is still shut down.

"We have been able to expose the line. We'll be able to assess repairs, hopefully within fairly short order and be sure we can engage in a safe restart of the line."

It is unclear when the line would be restarted.

Contaminated soils and trees are being removed from the site.

The spill comes two years after another Enbridge spill in Michigan.

The U.S. National Transportation Safety Board slammed the company's response to that leak, in which some three million litres of crude spilled into wetlands, a creek and the Kalamazoo River. The river was recently re-opened for recreational use.

White says Enbridge's response times have improved significantly.

"We detected this ourselves and the line was shut down within five minutes so that shows a very high level of control centre sensitivity and operations, response and public awareness," White said.

"People can rest assured that our goal is zero spills and we are improving towards that end but as operators we are constantly improving to be able to completely, thoroughly and officially address problems when they do occur."

Enbridge has been in the news recently for its proposed Northern Gateway pipeline.

The company wants to build a pipeline between Alberta and the West Coast so that Canadian crude can be shipped overseas to Asia by tanker and garner a higher price.

The Northern Gateway proposal met stiff resistance from B.C. First Nations groups and others.

The pipeline is also at the centre of an argument between B.C. Premier Christy Clark and Alberta Premier Alison Redford over how to fairly divvy up the project's risks and rewards.

Earlier in July, the company announced safety improvements, including thicker pipe and better monitoring that pushed the Northern Gateway project's price tag by $500 million to $6 billion.

With files from Amanda Anderson,, and The Canadian Press