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World Trade Center Health Registry

Assessing the physical and mental effects of the 9/11 attacks in NYC

In the aftermath of the terrorist attacks on September 11, 2001, there were concerns that immediate and ongoing exposure to dust and other environmental contaminants could potentially affect hundreds of thousands of people in the area around the World Trade Center. Questions arose about environmental toxins that might have been released from the collapsed buildings and ensuing fires and how those toxins or other irritants would affect the health of people exposed.

There was also concern about how the disaster would affect the mental health of the nearby population and those who played a role in rescue, recovery, and cleanup—in addition to the more apparent injuries suffered by survivors and first responders.

Tracking Short- and Long-Term Effects of Exposure

The World Trade Center Health Registry was established to

  • Identify and register people who were exposed to toxic substances
  • Assess the occurrence of physical injuries and mental health effects among survivors
  • Follow registrants over time
  • Identify people for future scientific studies
  • Plan and target public information and health education
  • Inform public policy related to the World Trade Center disaster and future environmental disasters

The registry includes rescue and recovery personnel, cleanup workers, residents, students and school staff, and building occupants and passersby in lower Manhattan. Implementation of the registry was a joint effort of the New York City Department of Health and Hygiene and the U.S. Agency for Toxic Substances and Disease Registry. For subsequent waves, additional support came from the National Institute for Occupational Safety and Health.

Establishing a Massive, Multilingual, and Multiwave Data Collection Effort

RTI played a key role in developing and implementing the registry, working with the sponsors to design and implement the initial survey. Our responsibilities included creating the database of potential registrants and assigning registrants to groups based on their likely level of exposure. We helped conduct a public outreach and media campaign, developed a web-based questionnaire for use in computer-assisted telephone and in-person surveys, conducted interviews in multiple languages, designed and tested the computer system, and developed and deployed a system and procedures for managing, processing, and delivering the data to the New York City Department of Health and Hygiene. Because registrants represented many countries and spoke a variety of languages, we administered questionnaires in the four languages most commonly spoken in the affected area—English, Spanish, Cantonese, and Mandarin.

Completed in November 2004, the first survey comprised 71,437 persons who enrolled and completed a 30-minute interview either over the telephone or in person. Eligibility for the initial study group was determined by qualifying for one of four categories of affected individuals:

  • Workers and volunteers involved in rescue, recovery, cleanup, or other activities at the World Trade Center site, material handling at the Staten Island Landfill, or debris transportation on barges
  • Residents at addresses located south of Canal Street
  • Students and school staff enrolled/employed in schools or day cares south of Canal Street on September 11, 2001
  • Building occupants, people in transit, and pedestrians who were present south of Chambers Street between the time of the first plane impact and noon on September 11, 2001

We conducted a follow-up survey from June 2011 to March 2012 to update information regarding the physical and mental health registry participants. The new survey focused on adult participants, including everyone who had enrolled in the initial adult survey and any children who had been enrolled by a parent or guardian who turned 18 years old on or before September 1, 2011. Of the 68,361 eligible enrollees, about 63 percent of eligible enrollees completed either a web, paper, or computer-assisted telephone interview for the follow-up.

Turning Data into Action—Helping Enrollees Find the Care They Need

The World Trade Center Health Registry has provided valuable information for establishing and guiding efforts to deliver physical and mental health care to those affected by the attacks in New York City on September 11, 2001.

One such initiative is the registry’s Treatment Referral Program, which reaches out to enrollees who completed the survey to address health problems, concerns, and questions the enrollees raised. The Treatment Referral Program sends enrollees an application form for the appropriate World Trade Center Health Program, if needed, and offers assistance with the application process.

Our survey and registry experts continue to work with the New York City Department of Health and Hygiene, reaching out to more than 67,000 eligible enrollees to conduct another round of follow-up surveys.