"We're using animal waste to reduce greenhouse gas emissions," said marketing director Ron Wardrop of Rothsay, which runs the plant.

"We need more of this type of thing," he said at the plant by the St. Lawrence River, near Montreal where 189 nations are meeting this week to work out how to curb climate change widely blamed on emissions of heat-trapping gases from fossil fuels.

Rothsay, a unit of Maple Leaf Foods Inc., is also making biodiesel at the plant by recycling oil from fast food restaurants, like from the deep-fryers used to cook french fries.

Biodiesel emits little of the smog of conventional gasoline or diesel fuel and almost none of the heat-trapping gases that most scientists say are driving up temperatures and could cause more floods, storms and rising sea levels in coming decades.

At full capacity, the Rothsay plant will produce 35 million liters (9.2 million US gallons) of biodiesel a year, the greenhouse gas equivalent of removing 16,000 light trucks or 22,000 cars from the roads.

"So far we're producing at about a quarter of capacity," Wardrop said. Production is a pinprick out of Canada's total diesel use of 2.2 billion liters.

PEANUT OIL

Biodiesel can also be made from farm crops, such as soy or canola. Germany's Rudolf Diesel, who built the first diesel engines in the 1890s, designed them to run on peanut oil.

Wardrop said he believed the Rothsay plant was the third of its kind in the world, along with one in Germany and one in Kentucky. Vehicles using biodiesel get tax breaks or subsidies from governments.

"Biodiesel is competitive in price, with the support of the government, with oil prices at $55 a barrel," Wardrop said. It would not compete if oil prices dropped to $20, he said.

At the Ville Ste. Catherine plant, the animal and fat waste arrives from a rendering plant as a thick brown liquid -- with a gut-wrenchingly rancid smell. It leaves as an almost odorless clear yellow fuel.

Biodiesel is produced by combining natural oils or fats with alcohols such as methanol or ethanol. The process leaves two products - biodiesel and glycerin.

"When you drive, some people say it smells of popcorn or french fries," said Claude Bourgault, general manager of Rothsay in the Quebec area.