Carbon pollution and what the federal government should do about it is under review in Denver.
The Environmental Protection Agency is holding one of 11 national listening sessions to gather feedback on potential carbon emissions limits for existing power plants on Wednesday. The hearing will be held at EPA's regional offices from 9 to 5 p.m.
Last month, the EPA introduced standards for new power plants. A proposal for existing plants isn't due until next summer and won't be finalized until 2015.
Colorado Lt. Gov. Joe Garcia and environmental activists are holding events urging officials to add carbon limits.
Opponents of the idea, including the Colorado and Wyoming mining associations, are holding a rally at 1:30 p.m. at the state Capitol.