Vermont landowners and conservation groups said they were looking for confirmation that Exxon Mobil and Canadian pipeline company Enbridge won't use an existing oil pipeline to deliver tar sands oil from the state.
Enbridge and Exxon's subsidiary Portland Pipe Line Corp. are reportedly looking to reverse the flow of the Portland-Montreal pipeline. The companies denied the claims but advocacy groups say pending applications in Canada suggest otherwise.
The companies involved in the pipeline at one point said they were putting the project on hold because of "economic and market conditions."
Jim Murphy, senior counsel at the National Wildlife Federation, said Vermont residents are concerned about the potential effects to the environment.
"Vermont is committed to a clean energy future," he said in a statement. "Tar sands development would send us past every climate tipping point scientists have warned of."
Critics say tar sands oil is the dirtiest form of crude though supporters say more pipelines are good for U.S. energy security and employment.
Vermont Natural Resources Council Energy Director Johanna Miller said the pipeline reversal would provide "no benefit to Vermonters."