"On February 12, 2007, President George W. Bush signed Homeland Security Presidential Directive 19 (HSPD-19) which deals exclusively with combating the domestic use of improvised explosive devices (IEDs). This directive defines an IED as 'an explosive device that is fabricated in an improvised manner incorporating explosives or other destructive, lethal, pyrotechnic, or incendiary chemicals.' Essentially, an IED is a bomb made with readily available materials intended to either disable or destroy personnel and/or equipment. While the task of rendering IEDs safe is typically handled by trained professionals, emergency responders should be familiar with the technologies involved in countering IEDs."
Department of Homeland Security: https://www.dhs.gov/