DENVER (AP) -- A rally organized by opponents of hydraulic fracturing drew about 200 people to Denver's Civic Center Park on Tuesday night.
Jakob Dylan of The Wallflowers, actress Daryl Hannah and others ended the four-hour Frack Free Colorado rally by singing "Stand By Me" on stage together.
Co-organizer Allison Wolff said the roughly $45,000 rally was meant to push for the acceleration of clean-energy alternatives and to educate the public on what Wolff called the dangers of hydraulic fracturing.
The process involves blasting water, sand and chemicals underground to free oil and natural gas.
Energy In Depth, the research arm of the Independent Petroleum Association of America, countered that fracking is safe and that both Republicans and Democrats have said U.S. natural gas production supports jobs and the nation's energy security.
The rally was modeled after a similar Songs Against Drilling event in New York, which used music to gain an audience for an anti-fracking message.
Hydraulic fracturing has allowed companies to extract gas in areas where it otherwise would have been economically impractical.
Colorado overhauled its oil and gas drilling regulations in 2008 and is working to update rules for how far wells must be from homes and other buildings. In Longmont, voters are being asked this November whether hydraulic fracturing should be banned.
Daniel Rodriguez of the Nederland-based band Elephant Revival, which also attended the rally, said, "I want people, including myself, to become more aware of how we use energy and how it's sourced."
His band has traveled using tour buses that run on biodiesel or vegetable oil.