when the towers fell, they caused dust to spread in new york city, and left hundreds of thousands of tons of debris at the site. the new york city fire department separated the site into four areas to make cleanup of the site and the search for people who survived the attack easier. early on, it was said that the debris at the site would take a year to get rid of, but cleanup ended in may 2002. building materials and debris from ground zero were sent to the fresh kills landfill in staten island.