On December 28, 2018, the U.S. Environmental Protection Agency (“EPA”) released a pre-publication version of a proposal revisiting the cost analysis underlying the Mercury and Air Toxics Standards (“MATS Rule” or “MATS”) for coal- and oil-fired electric generating units (“EGUs”) and conducting the residual risk and technology review required by the Clean Air Act (“Proposal”).  The Proposal would reverse a previous finding, issued by EPA under the Obama Administration, that regulation of hazardous air pollutant…