 The World Trade Center Health Registry was established in 2002 by ATSDR and the New York City Department of Health and Mental Hygiene to track the long-term physical and mental health effects of the September 11 attacks.The registry contains more than 71,000 people who lived, worked, or went to school near the World Trade Center site, as well as emergency response personnel who were involved in rescue and recovery efforts.It is the largest post-disaster health registry in the United States.