The September 11 attacks on the World Trade Center elicited a large response of local emergency and rescue personnel to assist in the evacuation of the two towers, resulting in a large loss of the same personnel when the towers collapsed. After the attacks, the media termed the World Trade Center site "Ground Zero", while rescue personnel referred to it as "the Pile". In the ensuing recovery and cleanup efforts, personnel related to the metalwork and construction professions would descend on the site to offer their services and remained until the site was cleared in May 2002. In the years since, investigations and studies have examined effects upon those who participated, noting a variety of afflictions attributed to the debris and stress. Building evacuation After American Airlines Flight 11 crashed into the North Tower (1 WTC) of the World Trade Center, a standard announcement was given to tenants in the South Tower (2 WTC) to stay put and that the building was secure. However, many defied those instructions and proceeded to evacuate the South Tower (most notably, Rick Rescorla, Morgan Stanley Security Director, evacuated 2,687 of the 2,700 Morgan Stanley employees in the building). People evacuating from WTC 2 were ordered up from the lobby level to a door on the mezzanine level that led to a covered footbridge over West Street to a building complex then called the World Financial Center. People evacuating from WTC 1 were directed from the lobby level through the WTC shopping mall beneath the outdoor plaza. The firefighters directing evacuees did not want anyone going through the front doors due to falling debris and falling people. Standard evacuation procedures for fires in the World Trade Center called for evacuating only the floors immediately above and below the fire, as simultaneous evacuation of up to 50,000 workers would be too chaotic. Emergency response Firefighters Firefighters from the New York City Fire Department rushed to the World Trade Center minutes after the first plane struck the North Tower. Chief Joseph W. Pfeifer and his crew with Battalion 1 were among the first on the scene (Battalion 1 was the first Unit to notify the Manhattan Central Office.). Engine 10 and Ladder 10 were also some of the first on scene, due to the fact that their firehouse was right across the street from the Towers. At 8:50 a.m., an Incident Command Post was established in the