Why the Registry Is Important

The World Trade Center Health Registry is now the largest registry in U.S. history to track the health effects of a disaster.

Enrollment in the Registry was voluntary for people who lived, worked or went to school in the area of the WTC disaster, or were involved in rescue and recovery efforts. To enroll, people completed a confidential "Wave 1" health survey (PDF) in 2003 or 2004. Each enrollee answered a series of questions about where they were on 9/11, their experiences and their health. This initial data allowed health professionals to compare the health of those directly exposed to the WTC disaster to the health of the general population. No blood tests or medical exams were required to enroll. Read more about the estimated number of people eligible for enrollment in the Registry (PDF).

The Registry completed its first follow-up survey "Wave 2" for adults (PDF) in 2007, and for children (PDF) the following year. In 2011, it launched its second follow-up survey "Wave 3" for adults (PDF), adolescents (PDF) and parents of adolescent enrollees (PDF). The fourth major survey, "Wave 4" for all age groups (PDF) and the asthma survey (PDF) were completed in 2015. The fifth major survey Wave 5 (PDF) for Adults was completed in 2021

The results of these surveys help determine to what extent physical and mental health conditions have persisted, and whether any new symptoms and conditions have emerged. Another important goal is to identify and help address gaps in physical and mental health treatment.

Registry findings are shared with:

• Enrollees and the public to help those affected by 9/11 make informed decisions about their health.
• Health researchers who are conducting studies about people affected by 9/11.
• Doctors and other medical providers who may treat people affected by 9/11.

In addition to completing Registry surveys, more than 90 percent of enrollees said they would be interested in participating in studies conducted by external researchers on the health effects of 9/11. Recent studies include depression, mortality, hearing loss and hospitalizations for asthma, among many others.

The Registry's publications include the quarterly e-Newsletter, past Annual Reports, health materials, as well as details on recent findings about the health consequences of 9/11.

Brief videos show some of our scientific findings.

If you or a loved one have a 9/11-related condition, we may be able to help.