The Associated Press reports that work to destroy the U.S. Army’s remaining stockpiles of chemical weapons may take longer and cost about $2.5 billion extra, Defense Department officials said. The latest projection added two years to the estimated schedule to finish the jobs at two remaining stockpiles and was described by one watchdog group as a “worst case” estimate. It also raised the total possible cost for the two projects to $10.6 billion, compared to $8 billion previously. Under the revised timeline, work to destroy chemical weapons at Pueblo Chemical Depot in Colorado might take until 2019.The project at Blue Grass Army Depot near Richmond, Kentucky, might take until 2023.