Flares Detonated at Florida's Eagle Ridge Mall, Not Pipe Bombs, FBI Says—Here's the Difference

Pipe bombs are typically cheap, easy to make and don't include military components. Wikimedia Commons

Following widespread reports that homemade explosives were detonated Sunday evening at Eagle Ridge Mall in Lake Wales, Florida, the FBI has determined that they were flares, according to the Palm Beach Post. The devices, which caused a lot of smoke but no injuries, were widely reported as pipe bombs.

"[Police] determined that an IED, or a pipe bomb explosive, had detonated in the corridor," Lake Wales Police Department Deputy Chief Troy Schulze said according to ABC. Two pipe bombs were initially believed to be responsible.

IMPORTANT UPDATE: Following initial reports from local police that fire at Eagle Ridge Mall caused by pipe bombs, FBI says no evidence of explosives found, fire ignited by flares. https://t.co/Bkv7XO7mg9@10NewsWTSP

— Josh Sidorowicz WTSP (@JoshWTSP) January 22, 2018

IED is catch-all term short for improvised explosive device. But, as WTSP reported, the devices were ultimately revealed to not be explosives of any kind, but Marine flares. "There is no indication of any explosion at the mall and no pipe bombs were found," the FBI said, according to Florida news channel WFLA.

IEDs are typically cheap and simple to design, according to the United Nations Office for Disarmament Affairs. The UN defines an IED as, "a device placed or fabricated in an improvised manner incorporating explosive material, destructive, lethal, noxious, incendiary, pyrotechnic materials or chemicals designed to destroy, disfigure, distract or harass." They can include military components, but typically don't.

Pipe bombs usually comprise four kinds of components, according to HowStuffWorks: a power supply (like a battery) an initiator (like a sealed PVC pipe or blasting cap) the explosive themselves (like nails, or a volatile substance like mercury fulminate) and finally a switch to trigger the initiator.

A larger version of a pipe bomb is called a pressure cooker bomb. This type of IED works by taking the gases associated with gunpowder explosions and placing them in a pressure cooker, the same kind you'd use to make food. As the gases expand, the pressure increases, resulting in a more violent explosion, according to Popular Science. This is what was used in the 2015 Boston marathon attack.

Flares, on the other hand, rely on the combustion of chemicals like strontium nitrate, potassium perchlorate and magnesium, which burns especially brightly. Their light is what makes them handy in emergencies, whether on boats or while driving on dark roads. The specifics of the flares believed to have been used in Florida weren't listed beyond the fact that they appeared to be military-grade, but those can still be purchased by civilians from sites like Amazon.

"We're definitely not calling it an act of terrorism at this point," Schulze said, according to the Washington Post. "That's up to the FBI."