May joined an anti-pipeline march in Montreal during which she questioned "the mania" of the Harper government's pipeline proposals, which she says involves shipping unprocessed bitumen across the country to be sent to foreign markets for refining.
"They are all of them -- Keystone, Energy East, Kinder Morgan and Enbridge -- unacceptable, no matter what kind of process one puts them through," she said.
May argued that the diluting agents that must be added to solid bitumen to make it liquid enough to flow through a pipeline also make the product more toxic than refined crude.
She said her party is in favour of a national energy plan that would limit the growth of the oilsands beyond current levels of production and push for processing bitumen in Alberta.
"Then we don't need to have any arguments about pipelines or trains because we're talking about finished product, refined product, that doesn't pose the same risks in transit," she said.
May said that previous plans to build upgrading plants in Alberta were shelved when investors pulled out due to the 2008 financial crisis. When the economy began to recover, she said the plans for in-province refining were replaced by pipeline proposals.
"It [Alberta refining] hasn't happened because the people making the decisions are making them in the interests of multinational big oil, not in the interest of Canada," she said.
"We have the right to say no to projects that make no sense, that provide no economic benefit to our provinces."
May was joined at Saturday's event by several of her local candidates. May held a banner and joined a symbolic "wall of women" as she joined a few hundred people on a loud anti-pipeline march through downtown Montreal.
May also had harsh words for Environment Canada who she said failed to act on Montreal's controversial plan to dump eight billion litres of raw sewage into the St. Lawrence River.
"I think it's unfortunate for Montreal that Environment Canada had all their plans more than a year ago and provided no assistance to come up with a better plan," May said.
Federal Environment Minister Leona Aglukkaq tweeted Wednesday that her office only learned of the wastewater dump plan last week and was "exploring options to prevent it while we get more information," but documents showed the federal government knew about the plan since 2014.
May accused Aglukkaq of "attacking" the city's plan after "giving them no help" to come up with an alternative to the short-term dump, which is scheduled to begin Oct. 18 as the city works to relocate a snow chute.
"It is very shocking that they couldn't come up with a better plan to divert this much sewage and not continue to treat the St. Lawrence like a sewer," she said.
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