Grist: Federal investigators are trying to figure out what caused an explosion at a West Virginia fracking site over the weekend. The blast injured at least seven people, including four workers who were sent to a hospital with life-threatening burns.
Residents and activists have long complained about safety practices by frackers operating in the state, where they draw natural gas from the Marcellus shale formation. Traffic accidents involving trucks traveling to and from frack sites in the state are...