The Democratic-controlled Senate has rejected a Republican bid to speed approval of an oil pipeline that would pass through Kansas.

The 56-42 vote Thursday was the latest in a series of Washington skirmishes over the Keystone XL pipeline, which would carry oil derived from tar sands in western Canada to refineries along the Texas Gulf Coast. Sixty votes were needed for approval.

President Obama rejected the proposed $7 billion pipeline in January, citing uncertainty over a yet-to-be-settled route that avoids the environmentally sensitive Sandhills region in Nebraska. Obama said there was not enough time for a fair review before a deadline forced on him by Republicans.

Pipeline supporters call it an important job creator. Opponents say it would transport “dirty oil” that requires huge amounts of energy and water to produce.