A Canadian pipeline company is cutting its ties with a controversial U.S. public relations firm after leaked documents raised concerns about suggested tactics to promote a planned pipeline.

TransCanada, based in Calgary, has announced it is no longer working with the multinational firm Edelman on its plans for the Energy East pipeline to bring Alberta's oilsands crude to eastern refineries.

In documents leaked to the environmental group Greenpeace, Edelman recommended that TransCanada secretly use third parties to attack the pipeline's opponents. Edelman also recommended TransCanada cultivate a "grassroots" movement of supporters using social media.

TransCanada immediately denied it had implemented those tactics, which were widely criticized.

"In the current environment, we can't have the respectful conversation that we want to have with Canadians and Quebecers about Energy East," TransCanada spokesman Tim Duboyce said Wednesday in a release.

"We need to discuss the project on its merits, responding to valid concerns such as how we will protect water and marine life, instead of talking about communications tactics."

Public skeptical, says Greenpeace

"Media reports have incorrectly suggested that TransCanada's communications practices are unacceptable," Duboyce said. "We are therefore starting a fresh conversation with all stakeholders. We want to be part of eastern Canadian communities for decades to come, and we want to do everything that will enable us to earn the trust of Canadians for the long-term."

They've got their work cut out for them, said Keith Stewart of Greenpeace.

"They're going to face a skeptical public," he said. "We want to see a different approach, not just a different PR
company. How the debate is conducted is always important to the substance of the debate."

TransCanada spokesmen have said they hadn't implemented the third-party strategy, although some of Edelman's advice is in play. The company will collect publicly available information on its opponents and has started an extensive social media campaign.