ISIS claims using 6,000 IEDs in 2013. By their very definition IEDs (improvised explosive device) are made of inconsistent materials. According to the Department of Homeland Security, here are some of the most well-known IEDs components in recent history:
- Semtex, C-4 (IRA, Various)
- Urea nitrate – (WTC, 1993)
- Ammonium nitrate and fuel oil (Oklahoma City Bombing, 1995)
- Smokeless Powder (Olympic Park, 1996)
- Ethylene glycol dinitrate ("Millenium Bomber," 1999)
- Triaceton Triperoxide (London, 2005)
IEDs most commonly found in Iraq are built inside artillery and mortar shells with a combination of homemade explosives. Unexploded landmines are also often modified to make IEDs. U.S. troops in Afghanistan often came in contact with "pressure cooker bombs." These IEDs often involved an actual kitchen pressure cooker packed with ammonium nitrate, gun powder, and metal fillings. Similar, if less sophisticated, pressure cooker bombs were used in the Boston Marathon bombing.