As law enforcement officials continue to search for a motive for the Christmas Day explosion in Nashville, analysts are turning their attention to a related and seemingly important question. When Anthony Warner blew himself up in his RV, he caused an incredible explosion. The explosion was big enough to damage pretty much every building on an entire city block. I’m sure there was quite a bit of space in this recreational vehicle, but it wasn’t that big. So what kind of bomb did he create that could create such destruction?
Some seasoned FBI blast investigators have checked the publicly available photos and videos and come to a rather surprising preliminary result. You describe Warner’s bomb as “unique in the annals” of improvised explosive devices used by terrorists. If they were correct, Warner would have had to create a very tricky design to create a significant explosion. Also, they suggest that officials should look for his test locations if we want to learn more about how he did it as there was no way he could have made it work the first time. (Daily Beast)
Find his test sites, say top bomb experts.
According to veteran FBI bombing experts consulted by SpyTalk, Anthony Quinn Warner’s device, while likely made up of common over-the-counter components, is unique in the annals of chaos.
“We have never seen an improvised thermobaric device in this country or in any other country,” says Dave Williams, who runs the FBI’s on-site investigation into the World Trade Center, Oklahoma City, Pan Am 103 and Unabomber Has carried out bombings incidents.
I was not familiar with the term “thermobar” before. Thermobaric explosions are generated using the oxygen in the ambient air to accelerate the rapid ignition of large quantities of gaseous fuels such as vaporized gasoline, propane, methane, acetylene or natural gas in an enclosed space. It’s the same principle behind stories of houses exploding when there’s a gas leak inside. However, according to these demolition experts, the process is extremely difficult, especially in a smaller space like the interior of a vehicle. The mixture of air and fuel has to be just right to create a really massive explosion. Too little fuel and you’re just creating a quick flash of flame that blows itself out. Too much and there won’t be enough oxygen for all of the fuel to burn.
That’s why they say Warner must have practiced several times to learn how to get the mix just right and maximize the power of the explosion. He obviously couldn’t practice in his house. We saw pictures of this house and it’s in a pretty dense suburb. Somebody would have noticed a series of gas explosions at some point and called the authorities. We’ve already learned that Warner’s ex-girlfriend tried to alert the police that her boyfriend was building bombs. Maybe she knows where he was practicing? I assume the FBI has asked her about it by now.
How did these experts come to the conclusion that Warner initially used a thermobaric bomb? Your first clue was the rapidly expanding yellow and orange fireball that is typical of a gaseous fuel-air explosion. Another factor they cited was how “clean” and efficient the combustion was, and initially produced almost no smoke. There was later some smoke from burning tires and other debris, but if the RV had been filled with something like ammonium nitrate fertilizer and heating oil (as used in the Oklahoma City bombing), the fuel itself would have created a massive puff of smoke in addition to the explosion. The same would be true if Warner had used dynamite or other conventional explosives. They create more of a shock wave of power and a lot of smoke, but not so much a ball of fire.
FBI analysts interviewed for this report seem to suggest that the need to build a timer to ignite the air-fuel mixture at precisely the right moment made Warner’s job even more difficult. But is that really true? Warner was in the motor home when it started. If he had been able to get some sort of equipment to monitor gas levels in the back of the vehicle, he could have manually ignited the cloud when it reached the optimal level. That would also have allowed Warner to switch from his recording warning of an imminent explosion to Petula Clark’s 1964 song “Downtown” as the gas levels neared the required concentration. (That’s still one of the strangest parts of this story.)
While the science behind this is very interesting, the depressing part is that Warner may have opened the door to other potential domestic terrorists who may be considering trying thermobaric explosive devices in the future. If you can overcome the problems of fuel concentration and ignition timing control, the materials required will be very common and harder to track than real explosives or unusually large fertilizer purchases.