Federal Government To Fine Canada For Wildfire?

     Sure it seems implausible...but if the U.S. Government has its way that's exactly what will happen under a proposed EPA law.  The Clean Air Act reads:

• The rule is not an executive order. Under the Clean Air Act, the E.P.A. is required to regulate any substance defined as a pollutant, which the law defined as substances that endanger human life and health. A 2007 Supreme Court decision led to an E.P.A. determination that carbon dioxide is a pollutant, thus requiring that the agency regulate it or be in violation of the law.

Therefore, if any of Canada's wildfire smoke enters US airspace they (Canada) will be at negligibly liable for lawsuits from the U.S. government.