The powerful U.S. Environmental Protection Agency has once again rebuked the State Department over its positive environmental assessment of TransCanada's proposed Keystone XL pipeline. In a lengthy, highly technical letter sent Monday to the top State Department officials overseeing the pipeline permit process, the EPA raises serious concerns about the project's carbon footprint and criticizes the department's draft analysis. It urges the State Department to rethink its finding that the controversial pipeline would not significantly spur production of Alberta's carbon-intensive oilsands or boost greenhouse gas emissions. The letter, signed by EPA official Cynthia Giles, said the State assessment included "insufficient...