A fact sheet from the National Academies and the U.S. Department of Homeland Security offers clear, objective information on improvised explosive devices (IED) attacks and their impact and dangers.  Created for journalists participating in the Academies' workshops on "News and Terrorism: Communicating in a Crisis," the fact sheet may be helpful to transportation agencies’ employees who could be among the first to respond to such an attack.  This fact sheet is part of a series on weapons of mass destruction.