[16] In 2007, the New York City medical examiner's office began to add people who died of illnesses caused by exposure to dust from the site to the official death toll.

As of August 2013[update], medical authorities concluded that 1,140 people who worked, lived, or studied in Lower Manhattan at the time of the attacks have been diagnosed with cancer as a result of "exposure to toxins at Ground Zero".

In interviews with 271 survivors, researchers in 2008 found that only about 8.6% had fled as soon as the alarm was raised while about 91.4% stayed behind to wait for more information or carrying out at least one additional task (collecting belongings/calling a family member).

[36] Just minutes after the plane crash, emergency responders arrived at the World Trade Center and began organizing teams to assist in the evacuation of the North Tower.

Executives such as Eric Eisenberg, who personally made the decision to evacuate AON's offices, instructed their employees to take the stairs down to the 78th floor Skylobby, where they could take an express elevator to the ground level and exit the building safely.

[62] Sean Rooney, a victim who worked for AON Risk Management on the 98th floor, was speaking on the phone to his wife seconds before impact, allowing some of the announcement to be heard in the background: "May I have your attention, please.

[67] A paramedic helping in the evacuation process remembered the air being so hot and thick that he had trouble breathing and difficulty seeing, but could hear the PASS device alarms of firefighters that had collapsed and needed assistance.

[citation needed] Not all of the evacuees were connected to World Trade Centers, with students from Stuyvesant High School, the Borough of Manhattan Community College, tourists, residents of the area with their pets and others, also involved in the evacuation process.

Because of communication difficulties between 911 operators and FDNY and NYPD responders, most of them were unaware that stairwell A was passable and instructed survivors above the impact zone to wait for assistance by rescue personnel.

[104][105] Daily Show host Jon Stewart and others succeeded in pushing for a law passed by Congress in 2015 that permanently extends health care benefits for the responders and adds five years to the victims' compensation program.

[131] Neil David Levin was the executive director of the Port Authority of New York and New Jersey, which was the governmental entity that built and owned the World Trade Center complex.

[147] Morgan Stanley lost very few employees that morning, though this was due in large part to their offices being located on floors below the plane impacts rather than any preemptive measures taken by the company.

Welles Crowther, a volunteer firefighter and equities trader for Sandler O'Neill and Partners on the 104th floor, similarly lost his own life while voluntarily assisting in the evacuation, whereby he rescued as many as 18 people.

[148] In spite of the decision being made to empty the floors occupied by Aon immediately following Flight 11's impact, the company still lost 175 employees in the South Tower,[149] the third highest death toll of any firm in the complex.

[150] Many elevators did not plunge when the planes crashed through, but were left stranded in the shafts, leaving their occupants to be burned alive in the fires or trapped and unable to escape before the towers collapsed.

[153] As the fires raged inside the towers, some 100–200 people plummeted at speeds of 125–200 mph (201–322 km/h),[154] sufficient to cause instantaneous death upon impact, but not enough to lose consciousness during the drop.

[155] In spite of the extremely limited number of victims documented, a fatal accident took place when a person landed on firefighter Danny Suhr as he prepared to enter the South Tower at around 9:30 a.m., crushing his skull and killing him.

[c] Most of the people who fell from the World Trade Center are believed to have intentionally jumped to their deaths to escape the extreme heat, thick smoke, chemical exposure and fire,[44] although a number of accidental falls were seen when victims stood too close to the edge or clambered outside.

However, damage done to the electronics by the airplanes precluded any possibility of this order being executed; in any case, thick smoke and intense heat would have prevented rescue helicopters from landing.

[169] In addition to the blaze being densely concentrated within a much smaller number of floors, the centralized impact dispersed burning jet fuel across all four sides of the tower, ensuring there was little to no leeway for those trapped.

[170] The airplane struck the South Tower's southern facade around 25 feet east of the center,[171] causing much more of the jet fuel to spray out into the open rather than spilling into the building.

The three people recorded falling came from a single window towards the southern portion of the 79th floor's east side,[173] where the worst of the damage had been inflicted and fires were at their most intense,[174] suggesting conditions were more tolerable elsewhere.

With a much lower impact zone of floors 77 and 85, as well as an entire side with no visible fires, those who survived Flight 175's crash were left with far more room to move away from the smoke and flames than those in the North Tower.

[81] While only 18 people from the trapped floors exited the South Tower safely, one NYPD unit crossed paths with a large group of civilians making their way down an unidentified set of stairs shortly before 09:58,[81] suggesting that other victims could have also been in the process of descending from the impact zone just prior to the collapse.

Solicitor General Theodore Olson,[199] retired U.S. Navy Rear admiral Wilson Flagg,[200] and women's gymnastics coach Mari-Rae Sopper[197] were aboard Flight 77.

On Flight 11, crew members Betty Ong[202] and Amy Sweeney[205] reported separately that several people had been attacked with knives, including a man (Lewin) who had his throat slashed.

[208][13][14][15] Below is a list of the nationalities of the foreign victims: During the attacks and afterwards, there was a large amount of toxic dust, debris and ash that was centralized around Ground Zero and created long-term health problems.

[260] Further, a medical director of the World Trade Center Health Program at Mount Sinai Hospital reported in 2018 that out of the approximately 10,000 first responders and others who were at Ground Zero and have developed cancer as a result, more than 2,000 have died due to 9/11 related illnesses.

The FDNY and NYPD had rotated hundreds, if not thousands, of different personnel from all over New York City to the pile which exposed so many of them to dust that would give them cancer or other diseases years or decades later.

[285] In 2021, four days before the 20th anniversary of the attacks, the New York City Medical Examiner's Office announced that the identification of the 1,646th and 1,647th persons: Dorothy Morgan of Hempstead, Long Island, and an unnamed man whose identity was withheld at the request of his family.