They now account for 40 per cent of the province's emissions of carbon dioxide – the main greenhouse gas – from industrial sources.
The stations continue to contribute a large proportion of many other air pollutants, including those that create smog, as well as large quantities of ash that contains mercury, arsenic and other toxic metals.
"The amount of pollution created by Ontario Power Generation's... plants is staggering. For many pollutants (they) tower above thousands of other facilities in the province," the report says. And, it argues, attempts to combat one type of pollution almost invariably lead to increases in others.
The report, "OPG: Ontario's Pollution Giant," was compiled using 2005 figures from the federal government's National Pollutants Release Inventory and its Greenhouse Gas Emissions Reporting Program, which track major industrial sources.
Its calculations show that, when it comes to air pollution, the coal-fuelled stations also account for:
- 22 per cent of Ontario's emissions that create smog and acid rain. Those pollutants include tiny particles, nitrogen oxides and sulphur dioxide.
- 24 per cent of emissions of the chemicals classified as toxic under the Canadian Environmental Protection Act. Many of these chemicals are believed to interfere with human reproduction and development. That includes 36 per cent of the mercury, which can damage the nervous system in humans.
As well, the coal stations produce about 3.4 million kilograms of toxic wastes contained in ash that's either landfilled on site or shipped elsewhere – mainly to kilns used to make cement at Bath and St. Mary's, Ont., and in Michigan, where it is burned as a fuel.
The alliance doesn't know whether these solid wastes pose a health threat, but there are concerns, particularly with kiln emissions, said alliance chair Jack Gibbons. "Kilns are significant sources of mercury."
Once again, in 2005, OPG's Nanticoke generating station, on the north shore of Lake Erie, was the province's biggest single source of carbon dioxide, particulates, nitrogen oxides and mercury. Nanticoke was second as a source of sulphur dioxide.
OPG operated five coal-fuelled stations until April 2005 when Lakeview, in southern Mississauga, was closed. The others are near Sarnia and in the Northern Ontario communities of Thunder Bay and Atikokan.
OPG spokesperson John Earl said the agency will continue to run the stations as efficiently as possible, and according to regulatory guidelines.