GRAND MARSH, Wis. – Canada’s Enbridge Inc. raced Sunday to repair a major pipeline that spilled more than 1,000 barrels of oil in a Wisconsin field, provoking fresh ire from Washington over the latest in a series of leaks.

The spill on Friday – almost two years to the day after a ruptured Enbridge line fouled part of the Kalamazoo River in Michigan – has forced the closure of a major conduit for Canadian light crude shipments to U.S. refiners and threatens to further damage the reputation of a company that launched a more than $3 billion expansion program just two months ago.

Enbridge said it intended to begin repairs to Line 14 late on Saturday after making “excellent progress” in cleanup, allowing for visual inspection of the line. But it still did not know what had caused the spill and provided no estimate on when the 318,000-barrel-per-day Line 14 would resume service.

An official with the U.S. Pipeline and Hazardous Materials Safety Administration said two inspectors were at the site on Sunday, and that all of the pooled oil had been cleaned up.

“The line has been uncovered to begin removing the failed section and send it to a metallurgical lab for examination,” agency spokesman Damon Hill said.

Officials from the Environmental Protection Agency and the Wisconsin Department of Natural Resources are also on site, Enbridge said in a statement.

Although the spill appeared to be relatively small and quickly contained, it comes at a delicate time for Enbridge, which suffered another leak in Alberta, Canada, a month ago and endured a scathing report from U.S. safety regulators over its handling of the Michigan leak in 2010.

“Enbridge is fast becoming to the Midwest what BP was to the Gulf of Mexico, posing troubling risks to the environment,” Rep. Edward J. Markey of Massachusetts, the top Democrat on the Natural Resources Committee, said in a statement.