World Trade Center Health Program
On September 11, 2001, 19 terrorists associated with the Islamist militant group al-Qaeda hijacked four passenger jets in a series of suicide attacks on the United States, killing 2,996 people and injuring more than 6,000 others. Hijackers flew planes into two main towers of the World Trade Center, resulting in the collapse of three buildings of the World Trade Center complex, and the Pentagon, resulting in the partial destruction of the western side in the building. The resulting dust cloud due to the collapse of the World Trade Center covered Manhattan for days and contained thousands of tons of toxic debris, including asbestos and other known carcinogens. Another hijacked plane crashed into a field in Shanksville, Pennsylvania following an attempt by the passengers to retake control of the plane. No one in the airliners survived.
As of 2011, approximately 18,000 people have received medical treatment for illnesses related to toxic dust from the World Trade Center site. A study of rescue workers released in April 2010 found that all those studied had impaired lung functions, and that 30–40% were reporting little or no improvement in persistent symptoms that started within the first year of the attack. In 2011 a major research study showed significant long term medical and psychological effects among first responders to the World Trade Center site. These effects include elevated levels of asthma, sinusitis, Gastroesophageal reflux disease and posttraumatic stress disorder.
American Airlines Flight 11
Rescue workers at the World Trade Center site began to discover body fragments from Flight 11 victims within days of the attack. Some workers found bodies strapped to airplane seats and discovered the body of a flight attendant with her hands bound, suggesting the hijackers might have used plastic handcuffs. Within a year, medical examiners had identified the remains of 33 victims who had been on board Flight 11. They identified two other Flight 11 victims, including purser Karen Martin, in 2006, while other unrelated body fragments were discovered near Ground Zero around the same time. In April 2007, examiners using newer DNA technology identified another Flight 11 victim. The remains of two hijackers, potentially from Flight 11, were also identified and removed from Memorial Park in Manhattan. The remains of the other hijackers have not been identified and are buried with other unidentified remains at this park.