The Department of the Interior is openly questioning a State Department impact study that effectively endorsed the Keystone XL pipeline. Released earlier this year, the long-awaited assessment concluded the Keystone XL does not threaten the global climate and would lead to fewer emissions than critics have alleged. The State Department’s review marked a major boost to the Keystone XL pipeline’s chances as President Obama mulls whether to approve or reject it. But in a newly released letter, the Interior Department says the review ignores the pipeline’s long-term threat to wildlife along its proposed route. The Interior Department is the second federal agency to challenge the State Department assessment after the EPA expressed similar reservations in April. The EPA singled out the review’s conclusion that building the pipeline will not adversely affect climate change nor impact whether tar sands oil is extracted.