State Inaction on Coal Plant Emissions Endangering Public Health Denver — Colorado is not in compliance with National Ambient Air Quality Standards for sulfur dioxide (SO2), a coalition of environmental groups charge. The coalition is formally asking the U.S. Environmental Protection Agency (EPA) to resolve the state’s non-compliance with this air quality standard within thirty days or face litigation. In June, the coalition consisting of Public Employees for Environmental Responsibility (PEER), the Center for Biological Diversity and five other community groups asked the State of Colorado to modify the coal power facility permits to address – Excessive amounts of SO2 being pumped into Colorado’s air by the Pawnee, Craig, Comanche and Hayden Generating Stations;