Environmentalists such as Dan Becker, director of the Sierra Clubs Global Warming and Energy Program, believes that the term clean coal is misleading: "There is no such thing as clean coal and there never will be. Its an oxymoron." The Sierra Club's Coal Campaign has launched a site refuting the clean coal statements and advertising of the coal industry.
Complaints focus on the environmental impacts of coal extraction, high costs to sequester carbon, and uncertainty of how to manage result pollutants and radionuclides. In reference to sequestration of carbon, concerns exist about whether geologic storage of  in reservoirs, aquifers, etc., is indefinite/permanent.
The palaeontologist and influential environmental activist Tim Flannery made the assertion that the concept of clean coal might not be viable for all geographical locations.
Critics also believe that the continuing construction of coal-powered plants (whether or not they use carbon sequestration techniques) encourages unsustainable mining practices for coal, which can strip away mountains, hillsides, and natural areas. They also point out that there can be a large amount of energy required and pollution emitted in transporting the coal to the power plants.
The Reality Coalition, a US non-profit climate organization composed of the Alliance for Climate Protection, the Sierra Club, the National Wildlife Federation, the Natural Resources Defense Council, and the League of Conservation Voters, ran a series of television commercials in 2008 and 2009. The commercials were highly critical of attempts to mitigate coals pollution, stating that without capturing  emissions and storing it safely that it cannot be called clean coal'.
Greenpeace is a major opponent of the concept, because they view emissions and wastes as not being avoided but instead transferred from one waste stream to another. According to Greenpeace USAs Executive Director Phil Radford speaking in 2012, "even the industry figures it will take 10 or 20 years to arrive, and we need solutions sooner than that. We need to scale up renewable energy; clean coal' is a distraction from that."