OTTAWA - Canada's refusal to support a legally binding global pact to cut highly toxic mercury pollution is another Kyoto-style evasion that allies Ottawa with Washington, critics say.

Canada sided with the U.S. and India during international talks in Nairobi this week. The trio was among a minority of countries that blocked immediate progress of an enforceable system to curb mercury use, including a glut of noxious exports to the developing world.

Instead, Canada favours voluntary reduction while talks continue.

Most of 58 countries represented, including the European Union, Africa, Japan and Brazil, supported a legally binding treaty.

"We've dropped the ball," said Ken Ogilvie, executive director of Toronto-based Pollution Probe. "We've once again settled into the same camp as the United States ... opposing a binding treaty and calling for voluntary initiatives that we have a hard time delivering effectively."

Environmental groups blamed the U.S. and Canada for effectively delaying an enforceable system. Repeated studies clearly document health threats posed by air pollution, water contamination and mercury-laced electronic junk, they say.

"They want more talk but they don't back up that talk with action," said Michael Bender, spokesman for Zero Mercury, a coalition of 48 public interest groups.

"What's really unfortunate is that Canada would not even consider supporting voluntary demand-reduction goals or looking at export restrictions," he said from Nairobi.

"The Canadian government really is not being proactive. If they tell you they are, they're not."

Environment Minister John Baird's spokesman stressed that the Conservatives will continue to discuss all reduction options with other countries.

Eric Richer also cited government plans to ensure mercury switches are removed before discarded cars are crushed for scrap metal. The small parts conduct electricity so lights come on when the hood or trunk is raised.

There's also a discussion paper before Environment Canada to assess mercury content in a range of products.

Critics say it's not nearly enough action. Mercury is a highly potent toxin that persists in the environment, builds up in the food chain and can neurologically harm humans.

The UN Environment Program, which hosted the Nairobi talks that ended Friday, says much of the developed world's mercury-laden e-waste - obsolete computers, cellphones and printers - is being dumped in African countries and other poor nations.

Mercury in large doses can damage the brain, nervous system and babies in the womb. Yet the heavy metal known as quicksilver is still widely used in processes ranging from mining to plastics and chemicals manufacturing.

Canadians are typically exposed through air pollution from coal-fired plants in Asia and the U.S., and through diets, especially in the Arctic, that rely on contaminated fish.

Canada conceded in documents submitted to the UN Environment Program that "there is sufficient evidence of significant global adverse impacts from mercury ... to warrant further international action to reduce the risks to human health and the environment."

Still, Ottawa favours voluntary reduction efforts while binding rules are discussed for the next two years.

Nick Nuttall, a spokesman for the UN Environment Program, says any legally binding treaty would have to be approved by a consensus of all member countries.

The good news, he said, is that "everybody accepts that mercury is a serious public health and environmental issue. Everybody is looking to act on mercury."

UN programs to curb its use will be stepped up over the next two years, he added.

But countries could not agree that binding rules are the way to go, Nuttall said. Still, voluntary co-operation - such as efforts to phase out lead from oil in sub-Saharan Africa - can work, he said.

Liberal MP and environment critic David McGuinty said it reminds him of the Conservatives' U.S.-style disdain for the Kyoto Protocol to cut greenhouse gas emissions.

"Foolish, very foolish," he said. "I mean, the government heralded its early work on mercury - most of which was done under our previous government.

"I'm reminded of the government in Washington. And that government has aggressively withdrawn from multilateral deals of all kinds over the last eight years.

"They want to simply say: 'We're going it alone.' ... But there's only one atmosphere. There has to be a global solution."