Toronto’s drinking water could be at risk due to a recent proposal to treat toxic waste at a plant on the New York side of Lake Ontario.

The Niagara Falls Water Board is exploring the possibility of treating excess fluid from hydraulic fracturing, or fracking — a method of extracting natural gas from shale — in the Adirondacks. The chemical-laden liquid would be transported to an existing waste water plant along the shores of Lake Ontario, home to an expansive ecosystem and the source of drinking water for more than 9 million people.

“This is a major new source of pollution,” said Lake Ontario Waterkeeper president Mark Mattson, who fears chemicals will seep into the lake. “Lake Ontario is already a threatened lake. It needs protection, not pollution.”

A 2008 report presented to the U.S.-based Ground Water Protection Council found that fracking fluids include a cocktail of chemicals common to cosmetics and automobile antifreeze.

Mattson said this is the first he’s heard of fracking fluid collected and transported to another water body.

“We don’t know the volumes, what they’re treating and we don’t have monitoring capability,” he said. “Ultimately, we’re going to be the ones most affected by the chemicals.”

One online video from a home in western New York, where companies drill along the Marcellus shale, shows a man lighting running tap water on fire.

The Council of Canadians issued a letter to the board on Thursday, suggesting waste water facilities are rarely able to fully decontaminate fracking fluid.

Currently, there are no treatment plants in the state equipped to handle the waste water, according to the New York State Department of Environmental Conservation.