Though the New York City Office of Emergency Management was responsible for coordinating the city's overall response in the aftermath of the World Trade Center collapse, the cleanup and recovery efforts at Ground Zero were quickly placed in the purview of the New York City Department of Design and Construction, a then-obscure Queens-based city agency that handled civic construction and permitting. From an elementary school in Battery Park City, DDC commissioner Ken Holden and deputy commissioner Mike Burton managed most of the day-to-day aspects of the site, along with an inner circle of consultants from the Port Authority of New York and New Jersey, Leslie E. Robertson Associates (founded by the lead structural engineer of the Twin Towers), LZA/Thornton Tomasetti, Mueser Rutledge Consulting Engineers, and D.H. Griffin Companies, as well as representatives from the Fire Department of New York, New York Police Department, the Port Authority Police Department, and various other state, federal, and nonprofit organizations.