Canadian pipeline company TransCanada aims to build the Keystone XL pipeline, which would carry oil from tar sands projects in Alberta province to refineries along the southern U.S. coast.
The pipeline, if built, would cross part of the Nebraska Sandhills and run through the Oqallala Aquifer, a key drinking water reserve.
Nebraska Gov. Dave Heineman, who has stated opposition to the pipeline, said Nebraskans deserve an assessment of alternatives.
"Therefore, I will be calling a special session of the Nebraska Legislature to have a thoughtful and thorough public discussion about alternative solutions that could impact the route of the pipeline in a legal and constitutional manner," he said in a statement.
Critics of Keystone XL complain pipelines carrying heavy crude from Alberta are prone to corrosion, noting Alberta crude lingers in the environment longer than conventional crude. Supporters point to the economic benefits and the boost to regional energy security.
TransCanada notes an extension of the existing Keystone pipeline from Steel City, Neb., to oil facilities in Cushing, Okla., has been in service since February.
The special Nebraska session is scheduled for Nov. 1.