SOUTH PORTLAND — The auditorium at Mahoney Middle School rocked Wednesday night with a standing ovation and cheers for a proposal that would block tar sands oil from coming into the city.

About 200 people, many of them wearing light blue “clear skies” T-shirts, attended a presentation on changes being recommended by the Draft Ordinance Committee.

The recommendations, to be considered by the City Council, would prohibit loading crude oil in bulk onto marine tank vessels and building or expanding facilities for that purpose. The proposal is much narrower in scope than the Waterfront Protection Ordinance that city voters rejected last November.

The ordinance committee’s report said 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.

“I am in awe of what you have done,” said Joann D’Orsay of South Portland, one of about 25 people who spoke in favor of the proposal. “I fear for our future generations breathing contaminated air.”

Not everyone at the meeting supported the proposed ordinance changes.

“I feel like you took a side and you’re subverting the vote of the city as a whole,” said Cliff Marchant of South Portland, one of three people who spoke against or questioned the proposal.

Marchant said he voted against the Waterfront Protection Ordinance and, while he hasn’t fully reviewed the new proposal, he believes the council should let the voters decide the issue again.

Later in the meeting, Mayor Gerard Jalbert joined several councilors in praising the committee’s work and said that naming the committee to develop a new proposal was the best way to avoid another divisive referendum.

The Waterfront Protection Ordinance was a citizen’s initiative that also was designed to prevent Portland Pipe Line Corp. from bringing tar sands oil into the city from Canada in an underground pipeline that now carries crude from South Portland to Montreal.

While the defeated ordinance would have blocked tar sands oil, it would have accomplished that goal by prohibiting expansion of all petroleum-related facilities on the waterfront, which many argued would have had an adverse effect on many other waterfront businesses.

Residents rejected that proposal by fewer than 200 votes in November. But the narrow margin, despite an opposition campaign backed by the oil industry, indicated to the council that the community has strong concerns about tar sands oil.

Environmental groups say tar sands oil is more dangerous to ship through pipelines and more difficult to clean up if spilled. Oil companies, including Portland Pipe Line, dispute those claims.

After the vote in November, the council enacted a moratorium on tar-sands-related development and created a committee to address the issue through ordinance amendments. That committee met 19 times for about 60 hours total.

Representatives of environmental groups and residents from neighboring communities also spoke in favor of the proposal.

Meanwhile, the Working Waterfront Coalition issued a statement Wednesday accusing committee members of going beyond their original charge to encompass all crude oil and “clearly signaling their long term goal of constraining and dismantling all of South Portland’s marine terminal operations.”

The coalition said the proposal “ensures that South Portland’s marine terminals have no ability to successfully evolve alongside the nation’s energy marketplace, which is currently enjoying a boom in domestic production. By constraining future terminal operations, the (committee) is ensuring the terminals’ inevitable decline and the loss of the local jobs they support.”

Burt Russell, vice president of operations at Sprague Energy, said “there’s no justification for such a ban, especially when this product has been safely transported, transloaded and stored on the waterfront for decades.

“This ordinance gives Sprague great concern for the sustainability of businesses on South Portland’s waterfront and the local people they employ,” Russell said.

Committee members said the proposal wouldn’t impact 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.

The council is scheduled to take an initial vote on the proposal July 7, followed by a Planning Board review July 15 and a final vote by the council July 21.