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People Affected by 9/11

Office Workers and Passersby

More than 43,000 World Trade Center Health Registry enrollees were office workers, commuters, passersby, or individuals in transit south of Chambers Street on September 11, 2001, representing more than 60% of all Registry participants.

Exposure among this group was substantial. More than 90% reported experiencing traumatic events on 9/11, nearly three-quarters were caught in the dust cloud, and thousands sustained injuries. Research has shown that these exposures contributed to long-term physical and mental health effects.

Five to six years after 9/11, approximately 8% of office workers and passersby reported newly diagnosed asthma. Dust cloud exposure and heavy dust contamination in workplaces were important risk factors. Registry studies also found that passersby experienced some of the highest rates of probable PTSD among all eligibility groups.

Research has further demonstrated the close relationship between physical and mental health. More than one-quarter of enrollees reporting either respiratory symptoms or PTSD experienced both conditions. Those with co-occurring conditions have reported significantly greater impacts on daily functioning and quality of life.

Over the past two decades, Registry researchers have continued to study respiratory disease, PTSD, chronic pain, quality of life, cognitive concerns, and other long-term health outcomes among office workers and passersby.

Tower Survivors

Nearly 8,500 adults who survived damaged or destroyed buildings in Lower Manhattan, including more than 3,600 evacuees from the World Trade Center towers, enrolled in the Registry.

Many survivors experienced multiple traumatic events, including witnessing the aircraft impacts, building collapses, injuries, and mass evacuations. Nearly two-thirds were caught in the dust cloud. More than 40% reported injuries ranging from cuts and burns to sprains and strains. Registry research found that around 15% of tower evacuees experienced probable PTSD several years after 9/11. Factors associated with increased risk included delayed evacuation, working on higher floors, sustaining injuries, and exposure to multiple traumatic events.

Registry researchers continue to examine the long-term physical, psychological, and quality-of-life impacts experienced by tower survivors more than two decades after 9/11.

Residents

Thousands of people living near the World Trade Center (WTC) site were exposed to dust, smoke, debris, and traumatic events following 9/11. Many residents were caught in the dust cloud, evacuated their homes, or returned to apartments contaminated with WTC dust.

In the weeks and months after 9/11, residents reported a range of health symptoms, including:

  • Coughing
  • Wheezing
  • Sinus problems
  • Eye and throat irritation
  • Headaches
  • Anxiety
  • Stress-related conditions

Children, older adults, and people with pre-existing health conditions were often among the most vulnerable.

More than two decades of Registry research have shown that some residents continued to experience long-term physical and mental health effects associated with their exposures. Studies have linked intense dust cloud exposure and heavy dust contamination in homes to increased risks of respiratory symptoms, asthma, post-traumatic stress disorder (PTSD), and other chronic health conditions.

Research has also demonstrated that health outcomes vary among individuals. Many factors can influence long-term health and recovery. Key factors include:

  • Age
  • Existing health conditions
  • Level of exposure
  • Socioeconomic circumstances
  • Access to healthcare

The Registry continues to study the long-term health of exposed residents, including respiratory disease, mental health, chronic pain, cognitive concerns, quality of life, and healthy aging. These findings help improve understanding of the lasting health effects of disasters and inform public health responses worldwide.

People Indirectly Affected by 9/11

The effects of 9/11 extended far beyond Lower Manhattan. Researchers have examined how media exposure, concern for loved ones, and the broader national trauma affected people across the United States and internationally.

Some studies found elevated levels of stress, anxiety, and post-traumatic stress symptoms among individuals who witnessed the WTC disaster through television and other media. However, long-term health effects were generally less pronounced than those observed among people who directly experienced the disaster.

Research consistently shows that direct exposure to traumatic events remains the strongest predictor of long-term PTSD and related health outcomes.

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