“In Lower Manhattan, the plane crashes—which resulted in the collapse of the Twin Towers—created massive dust clouds that filled the air and left hundreds of highly populated city blocks covered with ash, debris, and harmful particles, including asbestos, silica, metals, concrete, and glass. Fires within the debris pile and the collapse of 7 WTC burned through the end of December 2001 with continued flare-ups in 2002, releasing carcinogenic combustion by-products. These contaminants remained in Lower Manhattan and parts of Brooklyn for an undetermined amount of time after 9/11.”

Center for Disease Control and Prevention – CDC (https://www.cdc.gov/wtc/exhibition/toxins-and-health-impacts.html)