There are thousands of dirty old drill sites in Colorado. The state gave oil firms a $1bn pass

Investigation reveals regulator let firms off the hook on cleanup bonds despite backlog that will take decades to clearWhen Christiaan van Woudenberg moved to Erie, Colorado, in 2007, he never imagined he would become an anti-fracking activist. He simply thought he was buying his dream home – a four-bedroom with a panoramic mountain view, 30 minutes north of downtown Denver.Then, in 2014, the drilling started. Oil and gas rigs sprang up, some just 800ft (240m) from his bedroom window. The dream...