PHILADELPHIA (AP) — A federal prosecutor has moved to block plans to open what could be the nation’s first medically supervised injection site in Philadelphia. U.S. Attorney William McSwain has filed notice that he will appeal a judge’s ruling this week that found the plan legal. He has also asked a federal judge to stay the decision while the appeal unfolds. The move comes after residents shouted down former Gov. Ed Rendell and other Safehouse organizers at a press conference Wednesday. They want to open the facility at a medical complex in south Philadelphia, hoping it could save lives as the city grapples with about 1,100 overdose deaths each year.