SOUTH PORTLAND — A controversial proposal that would ban tar sands oil from coming into the city won the Planning Board’s endorsement Tuesday night.

The board voted 6-1 to recommend that the City Council approve the proposal as being “in basic harmony” with the city’s comprehensive plan.

Member Linda Boudreau opened the board’s discussion with a motion to recommend that the council vote down the proposed ordinance changes.

“The comprehensive plan doesn’t support the ordinance before us,” Boudreau said, adding that the plan aims to protect the oil industry and allow it to expand as needed with sufficient environmental protections.

Boudreau’s motion failed, and she provided the sole vote against supporting the proposal, with members Fred Hagan, Stefanie Veneziano, Kathleen Phillips, Caroline Hendry, Erick Giles and Chairman William Laidley voting in favor.

“I would rather be protecting the residents,” Hendry said. “Exporting crude is not the way the city should go.”

The board’s positive recommendation will be forwarded to the council.

The council voted 6-1 last Wednesday to give the proposal preliminary approval. A majority said the proposal would block tar sands while protecting existing jobs and uses.

The council is scheduled to hold a second reading and possibly take a final vote on the proposal on Monday at a location to be determined.

About 80 people gathered in a lecture hall at South Portland High School for the Planning Board’s review. It was far fewer than the nearly 500 people who turned out last Wednesday at the South Portland Community Center for the council’s preliminary vote.

The Planning Board heard testimony from about 20 people before voting, many of whom focused on the proposal’s correlation to the comprehensive plan.

Many supporters of the proposal wore familiar light blue “clear skies” T-shirts, but there were no red T-shirts worn by opponents at previous meetings.

The proposal would prohibit loading crude oil, including tar sands, in bulk onto marine tank vessels and would block construction or expansion of terminals and other facilities for that purpose.

The proposal was developed by the Draft Ordinance Committee after city voters rejected a broader Waterfront Protection Ordinance by a 200-vote margin in November.

That measure would have blocked the pipeline from bringing tar sands oil into the city using an underground pipeline that now carries crude from South Portland to Montreal. The defeated ordinance also would have banned expansion of petroleum-related facilities on the waterfront.

In developing its follow-up proposal, the ordinance committee found that loading crude oil onto a ship could increase air pollution, and that the vapor combustion facilities needed to mitigate the problem would have a negative visual impact on the waterfront.

Tar sands, also known as oil sands, are a mixture of sand, sticky raw petroleum and water. Environmental groups and others involved in the “clear skies” campaign say tar sands oil is more dangerous to ship through pipelines and more difficult to clean up if spilled.

Oil industry employees and representatives, including the Maine Energy Marketers Association, dispute those claims, saying that any restrictions are unjustified and would constrain business development, jeopardize jobs and block future crude oil shipping.

Supporters say the proposal is written to target tar sands oil from Canada, and note that it’s currently illegal to export U.S. crude oil, with some exceptions.

The proposal wouldn’t affect current uses or the handling of gasoline, diesel, biodiesel, ethanol, kerosene, No. 2 fuel oil, jet fuel, aviation gasoline, home heating oil, asphalt, distillate, waste oil, lubricants or other refined petroleum products.