9/11 Terrorist Attacks


On September 11, 2001, four planes were hijacked by 19 foreign-born terrorists with the intent of flying them into targets within the United States of America. Two planes, American Airlines Flight 11 and United Airlines Flight 175, originated from Logan Airport in Boston, MA and were flown into the World Trade Center (WTC), or twin towers, in the financial district of lower Manhattan, New York City. The first hit the North tower at 8:46 a.m., the second hit the south tower at 9:03 a.m. American Airlines flight 77 left Washington Dulles International Airport in Virginia at 8:42 a.m. and crashed into the Pentagon in Washington, DC at 9:37 a.m. A fourth plane, United Airlines Flight 93, originating from Newark International Airport, crashed landed in a field in Shanksville, Pennsylvania, at 10:03 a.m. after passengers overtook the hijackers.


The coordinated attack caused the collapse of the towers in New York (also referred to as “ground zero”), and the destruction of one wing of the pentagon, resulting in a total cost of more than $21.7 billion in government assistance and reconstruction aid and an additional $27.3 billion from economic decline for New York City alone. 2,996 lives were lost, (including the 227 passengers and crew on the planes and 19 terrorists), and thousands were injured.

World Trade Center fire/terrorism September 11, 2001. Emergency personnel outside One WTC.

World Trade Center fire/terrorism September 11, 2001. Emergency personnel outside One WTC.
(Richard B. Levine/Alamy Stock Photo)


The attacks were used as the rationale for U.S. engagement in Afghanistan starting October 7, 2001 and lasting until present day. These attacks were also used in part to justify a pre-emptive invasion into iraq on March 20, 2003, starting the Second Iraq War, which officially ended December 18, 2011. There remains a segment of the population that questions the validity of the events that occurred on 9/11, and consider the attack to be coordinated by the United States government perpetrated against it's own citizens. These claims are widely disregarded.

Economically, 9/11 caused a devastating blow to New York City's GDP. The Dow Jones Industrial Average dropped 14.3% the first week following the attack. 18,000 small businesses were displaced following the attack due to debris and the massive destruction to office and commercial space in lower Manhattan. North American air space was closed for days affected hundreds of thousands of flights.

The 9/11 Commission was established on November 27, 2002 to investigate and provide a complete report on the circumstances of the attack and provide a guide to response, preparedness and prevention. The report highlighted failures of both the Central Intelligence Agency and the Federal Bureau of Investigation. THe final report was published on August 21, 2004, after hearing testimony from members of various bureaus and departments, the executive cabinet, President George W. Bush, and past government officials. The Department of Homeland Security was established on January 24, 2003 to protect American citizens and coordinate between state and federal bodies to protection of infrastructure, transportation hubs, ports, and other potential targets of terrorism.

In October of 2012, a New York federal judge found Iran, the Taliban and al-Qaida culpable in the September 11 terrorist attacks and approved a $6 billion default judgment awarded to 47 victims, despite Iran's consistent denial of any connection to the attack. The James L. Zadroga 9/11 Health & Compensation Act, was signed into law by President Obama in early 2011, establishing the World Trade Center (WTC) Health Program and ensuring health care treatment for those affected by 9/11 through at least 2015.

Effects on public health

The most widespread health effect stemming from the 9/11 attacks was post traumatic stress disorder (PTSD). The Commissioner of the New York City Department of Health and Mental Hygiene reported that 19% of those in the immediate vicinity of the attack who sought medical treatment were still suffering from PTSD 506 years following the attack. In many instances these individuals lost friends and colleagues in the attack, suffered from respiratory or other illness caused by the debris cloud contaminants, witnessed the events first hand, or were involved in rescue operations.

In New York City, the dust cloud unleashed from the collapse of the towers contained hundreds of thousands of toxins which settled throughout lower Manhattan. Environmental reports did not return to normal until a year following the event. The debris also settled in the East and Hudson rivers. The first responders and clean up crews who operated in the vicinity during and following the attack have reported significant health effects as a result of inhaling foreign particulate matter after working in the debris field without adequate protective gear. In 2002 and 2009, two more people lost their lives as a result of the 9/11 attacks from dust, smoke, and contamination related illnesses. The city's medical examiner concluded that the ground zero dust was “harmful and even deadly.”

Within the first ten years following the 9/11 terrorist attack, the following health effects were disproportionately experienced by those in the WTC Health Registry: asthma, persistent abnormal pulmonary function, sarcoidosis (inflammation) of the lungs, increased risk of some cancers, sinus and lung problems, depression and high risk of suffering from PTSD.

Effect on the environment

The destruction of the World Trade Center is the greatest acute environmental distort in the history of New York City. The fires caused toxic gases to be emitted from the rubble in a plume of airborne combustion that burned for months. The collapsed buildings created debris that contained asbestos, polycyclic aromatic hydrocarbons (PCBs), dioxins, crystalline silica, pulverized glass shards, heavy metals, and thousands of other toxins resulting in dangerous chemical combinations in the air. While these contaminants certainly affected those in lower manhattan for the first year, as of 2010, sampling by the Environmental Protection Agency and independent studies showed no or low levels of contamination.

Public health role and response

National security threats remain despite the extensive amount of protections taken following the event. The Intelligence Reform and Terrorism Prevention Act of 2004 established the National Counterterrorism Center and required the Department of Homeland Security to take over pre-flight screenings of passengers from the Transportation Security Administration (TSA), closing security holes at airports and reducing the future risk of a similar attack.

The Departments of Homeland Security, Federal Emergency Response Agency, Environmental Protection Agency, and Center for Disease Control, among others, now have extensive guidelines for handling emergency repines, especially for terrorist attacks.

See also Asbestos ; Asthma ; Environmental Protection Agency (EPA) .



Government Publication Office (GPO). “The 9/11 Commission Report: Final Report of the National Commission on Terrorist Attacks Upon the United States.” Washington, D.C.: GPO, July 22, 2004. http://www.gpo.gov/fdsys/pkg/GPO-911REPORT/pdf/GPO-911REPORT.pdf


DePalma, A. For the first time, new York links death to 9/11 dust New York: New York Times, May 24, 2007. Accessed: October 15, 2012. http://www.nytimes.com/2007/05/24/nyregion/24dust.html?pagewanted=print

The City of New York. “What we know about the health effects of 9/11.” New York: Commissioner of the New York City Department of Health and Mental Hygiene. Updated: 2012. Accessed: October 19, 2012. http://www.nyc.gov/html/doh/wtc/html/know/know.shtml

Henry, S. and Jones, A. “9/11 responders wait for compensation for their illnesses.” CNN, September 11, 2012. http://www.cnn.com/2012/09/10/us/september-11zadroga-act/index.html


9/11 Memorial. Updated: 2012. Accessed: October 19, 2012. http://www.911memorial.org/

The September 11 Digital Archive. Center for History and New Media and American Social History Project/Center for Media and Learning. Updated: 2011. Accessed: October 16, 2012. http://911digitalarchive.org/

Alyson C. Heimer, MA

  This information is not a tool for self-diagnosis or a substitute for professional care.