Although carbon capture and storage has attracted a growing number of advocates, including environmental groups like the Natural Resources Defense Council, it has also attracted its fair share of detractors, such as Greenpeace, and skeptics including the U.S. Geological Survey's Yousif Kharaka (pdf), who has shown that leaking CO2 can make
surrounding water acidic, mix with brine and leach metals, and pose potential health risks to people and wildlife.