WATERVILLE — As North America slowly runs out of “sweet oil,” industrialists are turning to the more dangerous and dirty “oil sands” from Alberta, Canada, to power the economy, demonstrators said Sunday.

Oil sands, a low-grade petroleum called bitumen, also known as tar sands oil, would be transported along a 1,700-mile pipeline through the United States to refineries on the Gulf Coast if the controversial pipeline is approved this spring by the federal government.

The pipeline is called the Keystone XL pipeline and only President Obama and U.S. Secretary of State John Kerry can stop it, about a dozen people holding placards said Sunday outside the Unitarian Universalist Church in Waterville.

One of them had Obama’s phone number and gave it out for others to call.

“I know it doesn’t do much in Waterville, but we’re trying to get the message out, and we actually have the number of the president if anybody wants to call,” said Iver Lofving, of Skowhegan. “That number is — (202) 456-1111 — that’s the comment line for the president. Say don’t approve the Keystone XL Pipeline at all.”

Lofving quoted American author and environmentalist Bill McKibben who said the tar sands pipeline “is the fuse to the climate bomb” that kills the planet.

Others gathered around a “fake oil spill” of black plastic Sunday on snowbanks by the church agreed.

“We’re protesting the construction of the Keystone XL pipeline,” said 18-year-old Anselm Scheck of Waterville. “It runs from the tar sands in Alberta, where a source of oil has been discovered, through some of our most valuable heartlands.”

The oil sands industry is booming in Canada, pumping billions of dollars into the economy and providing thousands of jobs, according to a recent New York Times article. But critics say the processes for recovering the oil sands are particularly harmful to the environment.

President Obama is weighing climate concerns in his decision to approve the project and the State Department is considering whether to allow it to cross the border.

“We’re demonstrating because we are concerned about this pipeline. We don’t want approval of a pipeline down from Canada, across the United States, with oil in it,” said Jane Edwards of Winslow. “Basically it’s going to be up to the president, I believe.”

Dick Thomas, of Waterville, one of Sunday’s organizers, said tar sands oil is very thick and has the consistency of peanut butter. It’s mixed naturally 20 or 30 feet under the ground with sand and sometimes clay and is harvested by a process similar to strip mining of the land. He said there is a huge deposit of the stuff in Alberta, Canada.

“This is the second largest deposit of fossil fuel in the world,” Thomas said.

He said the tar sands oil is diluted with other petroleum products such as kerosene and is processed for transport — if the pipeline is approved — via the Keystone XL pipeline. He said the processing is expensive and requires a lot of burning of other petroleum products to get a final product ready for the refineries.

The fear also is that conventional oil spill technologies could not handle the heavy, tar-like bitumen that comes from the oil sands.

“This oil contributes 20 percent more to climate change because so much oil is burned just to process it.” he said. “We have run out of all the sweet oils, so now we are looking for what they call extreme oil.”

Thomas said he is a member of a local chapter of 350.org, an organization that focuses on climate change. Membership has more than doubled to 530,000 people since the group began fighting the pipeline in August 2011. In addition, about 76,000 people have signed a “pledge of resistance” sponsored by seven liberal advocacy groups in which they promise to risk arrest in civil disobedience if a State Department analysis points toward approval of the pipeline, according to the website.

The number 350 means climate safety: To preserve a livable planet, scientists say the amount of CO2 in the atmosphere must be reduced from its current level of 400 parts per million to below 350 parts per million.

Thomas said the U.S. government has until May 1 to make a final decision on whether to allow construction of the Keystone XL pipeline.

Doug Harlow — 612-2367 [email protected] Twitter: @Doug_Harlow