What Is an Incendiary Device? Austin Bomb Was Intended to Start a Fire

Another explosion rocked Austin, Texas on Tuesday night — the fifth in the past few weeks — this time at a Goodwill store. A 30-year-old man was injured in the explosion, and emergency response teams clarified that it wasn’t just a bomb that exploded. It was an incendiary device.

The word “bomb” is a blanket descriptor for a device designed to explode with a number of different effects. Generally, bombs injure people through shrapnel, or fragmented pieces of debris hurled through the air at high velocities. An incendiary device is a specific type of bomb, one that aims to injure and cause damage by starting a fire. Incendiary devices are filled with flammable chemicals like propane, thermite, and napalm, and can detonate on impact or with a timed detonator.

Incendiary devices have been used extensively in domestic and military conflicts throughout history to devastating effect. In their most primitive form — the molotov cocktail, for instance — incendiary devices have been used to light cars and buildings on fire during riots and less militarized conflicts.

But incendiary weapons have been most harmful when used in a coordinated military effort. During the Vietnam War, for example, napalm was repeatedly dumped over large swaths of land by the Vietnamese and U.S. Air Forces. It was also used during a massive firebombing in Tokyo in World War II, killing around 100,000 Japanese civilians. Napalm is such an effective, and cruel, chemical cocktail because it can burn unabated on most surfaces for up to ten minutes.

The horrors wrought by napalm use in Vietnam are well-documented. The most iconic photo from the war was taken by Associated Press photographer Nick Ut, who captured an image of 9-year-old Phan Thi Kim Phuc after she was hit by a napalm drop that burned the clothes off her skin.

While they aren’t necessarily more damaging than traditional shrapnel bombs, incendiary devices are a particularly cruel and imprecise explosive weapon. The U.S. government claims to no longer use napalm, and in 1980, the United Nations ruled that it was a war crime to use it in concentrated areas of civilians.