Four aboriginal groups appealed to Canada's biggest bank to use its corporate heft and political influence to stop Enbridge Inc. (ENB) from building a 725-mile pipeline to carry oil from Alberta's tar sands through northern British Columbia to Kitimat, where it would be loaded on tankers for shipment to the U.S. west coast or Asia.

They also spoke of rising cancer rates, depleted salmon runs and air and water pollution arising from the Alberta oil-sands projects. "Shareholders are contributing to the ecological disaster of Canada's natural resources," said Vice Chief Terry Teegee of the Carrier Sekani Tribal Council of British Columbia.

The Enbridge Northern Gateway Pipeline, as it's known, is the largest crude-oil pipeline expansion in North America, crossing mountainous terrain, hundreds of rivers and streams, and roughly 22 miles of key salmon spawning waters.

Royal Bank lends C$300 billion globally, of which 2%, or C$6 billion, are loans to the oil and gas sector. A "small share" of its energy loan book is lent to companies operating in the oil sands, Royal Bank Chief Executive Gord Nixon told shareholders.

Ryan Derange, known as Gitz Crazyboy, of the Athabasca First Nations, called the environmental impact from the tar sands an "environmental holocaust," and invited Nixon to visit his community to witness the fallout first hand. Nixon, who failed to deflect the invitation onto the bank's group head of strategy, treasury and corporate services, Barbara Stymiest, who did visit with various aboriginal communities last year, replied that he appreciated the invitation.

"We're a bank, not an oil company, not a government, and we're not even a leading lender to oil companies," Nixon said. "We're not siding with the oil companies, and we believe development has to be done in a responsible way."

The bank has in place "stringent" environment-related loan-covenant policies, he said.

More than 150 people protested the bank's involvement after the annual meeting.

"RBC has a decision to make. They can continue to align themselves with the tar sands, a project that is single-handedly compromising the climate, drinking water and the health of First Nations," said Brant Olson of San Francisco-based Rainforest Action Network, which also lobbied the bank at last year's annual meeting.

An Enbridge spokeswoman said that the company is in the final steps of preparing its environmental application, which will be submitted to the federal National Energy Board.