Ontario Power Generation operates six of the top ten dirtiest power plants in the province according to an environmental watchdog.
Toronto-based Environmental Defence Canada says two of the dirtiest OPG plants are here in Northwestern Ontario.
The Thunder Bay plant is ranked as number four on the list while the Atikokan Generating Station is number five.
Based on eight months of data from 2000, Environmental Defence Canada says Ontario Power Generation plants led the pack of polluters producing more than 26 million tonnes of air pollution in the province.
The watchdog group posts all of its results on a website, www.airwatch.ca.