The TOPOFF 4 Full-Scale Exercise builds on knowledge derived from earlier TOPOFF exercises and recent real world events, and contains several new elements: (1) Increased coordination with U.S. Department of Defense exercises to combat global terrorism (2) Expanded emphasis on prevention - the opportunity to piece together an intelligence puzzle and stop an attack before it occurs (3) Focus on mass decontamination and large-scale recovery and remediation issues (4) Focus on coordinating procedures and communications with a U.S. territory (DHS, TOPOFF 4: Exercising National Preparedness, Press Release, September 25, 2007)