MONTPELIER, Vt. — If the owner of an oil pipeline that runs between Quebec and Maine wants to move tar sands oil from Montreal to Portland it would need a new state land-use permit, a regional environmental official ruled Monday.

The Portland-Montreal Pipeline Corp. had asked the District 7 environmental coordinator to reconsider a ruling issued earlier this year that an Act 250 land-use permit would be needed in the event the company seeks to reverse the flow of oil in the pipeline, which currently carries oil from Portland to Montreal through northeastern Vermont and northern New Hampshire.

The decision issued Monday confirms the earlier decision, saying that reversing the flow would be a significant change to the existing use of the pipeline that would require extensive modifications.

“The above physical changes are not routine maintenance or repairs. The changes are a series of modifications specific and requisite to a change in the pipeline’s use,” said the ruling.

Pipeline officials have said they have no plans to reverse the flow, but they have been looking at other business uses for the line.

Some environmentalists worried that moving diluted tar sands oil from Alberta through the line would increase the likelihood of a spill. It would also encourage the use of tar sands oil, which some believe contributes more to global warming than traditional crude oil.

It could take several years for the company to get an Act 250 permit.

Officials with the pipeline company did not immediately return a call Monday seeking comment.