The16-acre Ground Zero site is under a unified command : the diggers are city law enforcement officers and firefighters, engineers from the city's Department of design and construction, and an army of union laborers. 面积16英亩的爆炸现场处于统一指挥之下:挖掘者是城市执法官员和消防员,市规划建筑局的工程师,以及一批工会工人。