In Iraq many of the Islamic terrorist bomb builders who survived the 2003-8 campaign are back in business and ISIL (Islamic State in Iraq and the Levant) is their main customer. While the Islamic terrorists lost the 2003-8 campaign they did learn what worked. Most of the ISIL leadership also belonged to the pre-2008 Iraqi al Qaeda movement they are apparently familiar with what worked back then (before 2008). ISIL’s enemies remember as well thus the effort to damage ISIL access to cash, weapons and bomb building materials revealed that many of the same sources (smugglers, corrupt merchants and improvised materials) are being used to build bombs for ISIL.
ISIL knows that not only were IEDs (Improvised Explosive Devices) a very effective weapon against Americans before 2008 but against anyone at any time. The United States revealed that after September 11, 2001 two-thirds of Americans killed in combat were the victims of roadside bombs and (much less often) mines. This was a big shift from the American experience in Vietnam, where 14 percent of American deaths were from IEDs and mines. While that meant twice as many Americans killed by bombs and mines during Vietnam (55,000 dead) compared to Iraq and Afghanistan (6,700 dead), the IEDs became the most successful weapon the enemy had against American troops.
Now the Iraqi government is discovering that the greatest cause of casualties is not ISIL bullets but ISIL bombs. American advisers are urging Iraq to use American (actually Israeli) tactics to cripple this ISIL weapon. That means concentrating on ISIL leaders (especially those in charge of obtaining supplies) and technical specialists (bomb builders) and the IED effort will be crippled. That worked in Iraq before 2008 and in Afghanistan to this day. Iraq acted on the American advice but what these operations tend not to get covered much in the media. There were many epic struggles in Iraq which often ended up in the IED gangs going down. It takes time, but the pressure causes the gangs to spend less time concealing IEDS, and building smaller or less reliable ones. As more key people are lost, the IEDs efforts gets sloppy, and the enemy losses accelerate.
ISIL is also borrowing another trick from the pre-2008 playbook. As happened eventually in Iraq bomb builders ran out of artillery shells and other conventional explosives and had to depend on ammonium nitrate fertilizer to create explosives. The bomb builders can also use potassium chlorate which is more expensive than ammonium nitrate but not to the point where the terrorists cannot afford it. Potassium chlorate is a common industrial chemical used for all sorts of things, including fireworks and matches.
Ammonium nitrate is a powdered fertilizer that, when mixed with diesel or fuel oil, can be exploded with a detonator. While only about 40 percent of the power as the same weight of TNT, these fertilizer bombs are effective as roadside bombs. But they are bulkier and a slurry, usually mixed in a plastic jug or a barrel. Moreover, the fuel oil must be mixed thoroughly and in exactly the right proportion, otherwise the explosive effect is much less than expected.
All other bomb components can also be obtained by using non-military components. This is what makes it so difficult to cut off the ISIL supply of bomb components. But the known bomb builders in Iraq and Syria are still a target, especially for air delivered smart bombs and missiles.