PORTLAND — After nearly two hours of public testimony, after protests and petitions, and after a rejected attempt four months ago to ban the city’s use of fuel made from it, a City Council vote Monday against piping “tar sands” oil seemed to hinge on a single word.

The council voted 7-2 to approve a resolution expressing “concern” about the possibility of transporting tar sands near Portland – a resolution that was amended from a proposed one expressing “opposition.”

The wording was changed after Councilors Ed Suslovic and Nicholas Mavodones Jr. said they had doubts about information used on both sides of the controversial tar sands issue.

Tar sands are a sludge-like mixture of sand, oil, clay and an oil known as bitumen. Some environmental advocates say Canadian energy company Enbridge intends to pump a diluted form of tar sands 236 miles through the 72-year-old Portland-Montreal Pipeline. But because tar sands are more corrosive than other types of crude oil, the advocates claim, they could damage the pipeline and endanger nearby water resources.

Environmentalists also say that increasing the extraction, refining and eventual use of tar sands will increase greenhouse gas emissions and be a disastrous “game-changer” for the earth’s climate.

However, proponents of using tar sands claim their physical properties are no different from those of other “heavy” crude oils that have been safely piped for decades. And in an oil-hungry world, tar sands must inevitably be tapped, the proponents say.

On Monday, more than 40 members of the public testified; all but six supported the resolution. Most speakers repeated arguments raised when the council considered the tar sands ban proposed in January.

Still, there were some new claims.

Eliot Stanley, of the Sebago Lake Anglers Association, informed the council that the Portland-Montreal Pipeline runs inside city limits for about a mile, near the Portland International Jetport. It had been widely understood that the pipeline was not within Portland, so the city would have no jurisdiction in opposing its use for tar sands.

One of the opponents to the resolution was Walter Russell, a Yarmouth resident who works as a ship pilot in Portland Harbor. Russell praised the safety record of the pipeline’s owner, Portland Pipe Line Corp., and said that not allowing it to operate profitably by pumping tar sands would be economically disastrous.

“This is going to kill business in the port,” he said. “A lot of people are going to be impacted economically.”

After public comment wound up, councilors had their turn.

Suslovic and Mavodones asked Ian Houseal, the city’s sustainability coordinator, about upcoming studies and other sources of information that might provide clear answers about the risks of tar sands. But Houseal could offer little help.

“We’ve heard a lot of conflicting information,” Suslovic said in response. “I feel at this point that it’s premature to call for opposition.”

Mavodones said that for him “it’s important that we have the best available data … but I don’t feel, based on the data before me, I can oppose (tar sands).”

After the council amended the resolution by a 5-4 vote, Mayor Michael Brennan scolded the council for watering down the language.

“I am very disappointed,” he said angrily, noting that the council’s Transportation, Sustainability and Energy Committee worked for over a year to develop the resolution and recommended it unanimously.

“If we’re not opposed to tar sands coming through southern Maine,” the mayor said, “we should be opposed to how it’s procured.”

Brennan cast one of the dissenting votes. Councilor Cheryl Leeman cast the other, after responding to Brennan.

“Just because something has gone through the committee process doesn’t mean it has (the council’s) stamp of approval,” Leeman said.

But she, too, was troubled by the conflicting information.

“I don’t have clarity,” she said. “I just can’t seem to get my arms around the facts.”

Councilor David Marshall, who heads the TSE Committee and has been an outspoken supporter of the resolution, seemed unfazed by the wording change.

“I’m personally very concerned (about tar sands),” he said. “I’m also opposed.”

William Hall can be reached at 781-3661 ext. 106 or whall@theforecaster.net. Follow him on Twitter: @hallwilliam4.