The collapse of the Twin Towers coated Lower Manhattan in a blanket of toxic dust, and fires at Ground Zero continued to smolder for months after the attacks. Many first responders who were active in the initial rescue and recovery effort reported respiratory issues, and the CDC estimated that as many as 400,000 people in the surrounding area had been exposed to potentially harmful substances or severe physical or emotional stress as a result of the attacks. A monitoring and treatment program created in 2011 tracked the health of more than 100,000 people who had been exposed to harmful “9/11 agents.” Among the most common issues reported were chronic sinusitis, GERD, an assortment of cancers, and PTSD. By 2023 more than 5,700 participants in that program had perished; at that time, it was estimated that the number of lives claimed by September 11-related illness had far surpassed the total lost in the attacks themselves.