Findings

These findings are based on Registry data collected in late 2003 and 2004.  Results of the Registry’s first follow-up survey will be posted here later in 2008.

Estimated Number of People Exposed

Approximately 410,000 people were heavily exposed to the WTC disaster, including:¹

• More than 91,000 rescue and recovery workers and volunteers
• More than 57,000 residents south of Canal Street
• About 15,000 children and staff in schools (pre K-12) south of Canal Street
• More than 360,000 building occupants, residents and people passing by

Types of Exposure

Among the 71,437 people enrolled in the WTC Health Registry:²

• 70% reported witnessing traumatic events including seeing people as they fled from the dust cloud (53%); collapsing buildings (47%); people being injured or killed (33%); people falling or jumping from a building (29%); or an airplane hitting a building (29%)
• 51% reported being in dust cloud from the collapsing WTC towers
• 13% sustained an injury
• 61% of adult residents reported that they evacuated their homes on or after 9/11, with 9% returning as early as two days later
• 83% of building occupants reported they evacuated their workplaces on 9/11

Health Effects of WTC Exposure

Among adult Registry enrollees:²

• 67% reported any new or worsening respiratory symptom including persistent cough, shortness of breath, wheezing, throat irritation or sinus irritation after 9/11
• Nearly 3% of adult enrollees reported newly diagnosed asthma two to three years after 9/11
• 16% screened positive for current PTSD and 8% for serious psychological distress, including depression and anxiety, two to three years post-9/11
• Respiratory problems and mental health conditions were more likely among enrollees who reported being caught in the dust cloud, witnessing a traumatic event or sustaining an injury
• Rescue and recovery workers and volunteers reported the highest rates of newly diagnosed asthma
• The prevalence of PTSD was highest among building occupants, passersby and people in transit the morning of 9/11

Based on these findings, the Registry estimates that among the 410,000 people heavily exposed to the WTC collapse:²

• 124,800-232,200 experienced new or worsening respiratory symptoms after 9/11
• 3,800-12,600 had newly diagnosed asthma two to three years later
• 34,600-70,200 developed probable PTSD and 9,700-20,000 people experienced serious psychological distress two to three years post-9/11

Effects of Dust Cloud Exposure

Most people caught in the WTC dust cloud, and many people exposed indirectly, had acute physical symptoms after 9/11, including sinus problems, cough and eye irritation.³

For tower survivors and those from nearby damaged buildings, people caught in the dust cloud had the highest risk of respiratory symptoms and psychological distress. The greater the dust cloud exposure, the higher the likelihood of symptoms.⁴

A Closer Look At Asthma

Among rescue/recovery workers enrolled in the Registry, 3.6% reported newly diagnosed asthma after 9/11, a rate substantially higher than normal for the general adult population. Workers who arrived at the WTC site on 9/11 or 9/12, and those who worked more than 90 days, reported the highest rates of new asthma (7%).⁵

Workers who wore respirators on 9/11 and 9/12 reported newly-diagnosed asthma at lower rates (4.0% and 2.9%, respectively) than those who did not (6.3% and 4.5%). Though respirators were shown to be protective, all workers, including those who wore masks, had higher rates of new-onset asthma.⁶

The asthma rate reported for children under age five in the Registry may be as much as twice the rate found in the northeastern U.S. for the same age group.⁶

A Closer Look At PTSD

Registry findings also revealed that rescue and recovery workers exhibited symptoms of post-traumatic stress disorder (PTSD) when they were interviewed in 2003 and 2004, at a rate three times higher than normal for the general adult population. Workers with no prior training or experience with traumatic situations had the highest rates of PTSD.⁷

One in eight (13%) Lower Manhattan adult residents exhibited symptoms of PTSD two to three years after 9/11. Residents who reported injury, witnessing horror, and dust cloud exposure were at increased risk for PTSD, as were lower income residents and those forced to evacuate.⁸

References

1. Murphy J, Brackbill RM, Thalji L et al. Measuring and Maximizing Coverage in the World Trade Center Health Registry . Statistics In Medicine. 2007. 26: 1688-701.
2. Farfel M, DiGrande L, Brackbill R et al. An Overview of 9/11 Experiences and Respiratory and Mental Health Conditions among World Trade Center Health Registry Enrollees. Journal of Urban Health: Bulletin of the New York Academy of Medicine (in press).
3. New York City Department of Health and Mental Hygiene. World Trade Center Health Registry Data Snapshot . November 2004.
4. Brackbill RM, Thorpe L, DiGrande L et al. Surveillance for World Trade Center Disaster Health Effects. Morbidity and Mortality Weekly Report. 55 (No. SS-2) April 2006.
5. Wheeler K, McKelvey W, Thorpe L et al. Asthma Diagnosed after September 11, 2001 among Rescue and Recovery Workers. Environmental Health Perspectives. 2007. 115:1584-1590.
6. Thomas, P, Brackbill R, Thalji L, et al. Respiratory and Other Health Effects Reported in Children Exposed to the World Trade Center Disaster of September 11, 2001 . Environmental Health Perspectives. 2008 October;116(10):1383-1390.
7. Perrin MA, DiGrande L, Wheeler K et al. Differences in PTSD Prevalence and Associated Risk Factors among World Trade Center Rescue and Recovery Workers. American Journal of Psychiatry. 2007. 164:1385-1394.
8. DiGrande L, Perrin M, Thorpe L et al. Posttraumatic stress symptoms, PTSD, and risk factors among Lower Manhattan residents 2-3 years after the September 11, 2001 terrorist attacks. Journal of Traumatic Stress, 2008.21(3)264-273.