Greenwire: U.S. EPA is considering two former Halliburton Co. executives along with one of the most outspoken critics of hydraulic fracturing to provide independent expert advice on its study of the polarizing drilling practice. The EPA Science Advisory Board’s “short list (pdf)” of 82 people to serve on a review panel could reignite a debate that dogged a previous fracturing study, in which a Halliburton employee served on a peer review panel that was criticized for being overloaded with people …