OTTAWA -- Opposition leader Thomas Mulcair expanded his attack on Western Canada's resource industries, comparing the oilsands to Sydney's tar ponds - a notorious toxic waste site in Nova Scotia.

During a debate on the economy Thursday, Conservative MP Chris Warkentin accused the NDP leader of wanting to "go after industry in my province of Alberta" by putting a price on carbon emissions.

That's when Mulcair mentioned the mess left by the coke ovens of Cape Breton steel plants.

"If you look at the Sydney tar ponds - it is TAR, not oil," Mulcair said. "It's a mistake from decades ago that we're cleaning up."

Mulcair said future generations will "be left with a bill for tens of billions of dollars of cleanup and entire ecosystems that will have been destroyed" unless oil companies are forced to pay for any pollution.

Like former Bloc Quebecois leader Gilles Duceppe before him, Mulcair also accused the Conservatives of favouring Alberta's oil industry with subsidies, and pushing oil and gas exports.

"That is contributing to keeping the Canadian dollar artificially high, which of course, everyone admits ... is the principal cause of at least 50% of manufacturing job losses," he said.

The Liberals -- still remembered in the West for the Trudeau-era National Energy Program -- jumped on Mulcair's comments.

"Will he apologize to Western Canadians for his attack on Western Canada and acknowledge that all of Canada benefits by all of the natural resources?" Kevin Lamoreux said.

The Winnipeg MP also reminded Mulcair of a recent speech by Bank of Canada governor Mark Carney thatconcluded higher commodity prices are "unambiguously good for Canada."

Supporting an NDP motion that calls on the prime minister to attend a first ministers' economic conference, Mulcair criticized Stephen Harper for only attending one such get-together.

Heritage Minister James Moore says Mulcair needs to mend his own fences after once dismissing Western premiers as Harper's "messengers."

"That's an irresponsible position from somebody who wants to be prime minister of this country - to attack other premiers whom he has never met and doesn't know," Moore said.