CASCO – A flotilla of about 100 people in inflatable tubes, kayaks decorated with protest signs, and canoes showed up at Sebago Lake State Park on Saturday to rally against using the Portland to Montreal pipeline to transport tar sands oil.

They were joined by another 100 people on shore who were there to voice their opposition to reversing the flow of the pipeline to allow oil from western Canada to be transported to Portland Harbor.

The pipeline runs 236 miles, crisscrossing rivers and wetlands and passing within 500 feet of Sebago Lake, the source of drinking water for Greater Portland.

“This is the first bathing suit rally I have been to,” said Ian Smith of Portland.

With temperatures in the low 90s, the conditions were a contrast to the bitterly cold conditions at an anti-tar sands rally in Portland in January that drew 1,400 marchers.

Saturday’s event was organized by 350 Maine, a group trying to end fossil fuel dependence; Concerned Citizens of South Portland, which gathered enough signatures to put the tar sands issue on the ballot in South Portland, where the pipeline ends; and other environmental groups.

Pipeline opponents say tar sands oil is more corrosive than conventional crude and poses a greater risk for a spill. They also say burning more oil from the deposits in western Canada will pump large amounts of carbon dioxide into the atmosphere, spurring on climate change.

The Portland Pipe Line Corp., which operates the pipeline, pump stations and tank farms in South Portland and Montreal, has said it has no specific plans to reverse the flow but has acknowledged such a move would boost its business.

The corporation has said the tar sands oil can be transported as safely as the millions of barrels of overseas heavy crude that have moved through the pipeline since it was built in 1941.

Proponents point to a recent draft environmental impact statement on the Keystone XL pipeline, which would run from Alberta to the Gulf Coast. The statement noted that tar sands oil is the same as crude and posed little risk of a spill.

Saturday’s rally included an appearance by Bill McKibben, author and founder of 350.org, an organization that is campaigning against climate change.

McKibben said the movement to end the world’s reliance on fossil fuels is making progress.

“The good news is I think we are going to stop a lot of this insanity,” he said.

McKibben pointed to countries such as Germany, which has been able to generate half of its power from solar panels on some days this summer.

Beth Quimby can be contacted at 791-6363 or at:

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