Tannerite explodes when struck by a bullet from a high-powered rifle so ranges put it on targets as a way to prove a target has been struck. Binary explosives do have an inherent degree of safety, in that they aren’t explosive until the two parts are mixed. The Bureau of Alcohol, Tobacco, Firearms and Explosives defines binary explosives as pre-packaged products consisting of two separate components – typically an oxidizer like ammonium nitrate and a fuel like aluminum or another metal. Tannerite cannot be set off by a smoldering fuse, an electronic fuse, an electrical current, an open flame, impact with a hammer or even a low-velocity handgun, according to Steve Yerger, a corporate investigator for Tannerite. Like all explosive reactions, it works because the products are more stable than the starting components. A federal law enforcement official who was not authorized to speak publicly about the ongoing investigation confirmed that investigators found Tannerite residue the bomb that exploded in Chelsea, injuring 29 people on Saturday night. Tannarite makes it easy for shooters at a range to easily determine whether their shot hit its intended target, Yerger said. You can buy it online or in stores, and the individual components are available on their own. The ATF does not regulate the sale and distribution of the two chemicals used in Tannerite and similar products, even when sold together in binary "kits," the ATF said. USA TODAY 2 of 25 Skip in Skip x Embed x Share CLOSE EXPLOSION IN CHELSEA NEIGHBORHOOD OF NEW YORK CITY Photographer describes the capture of Ahmad Khan Rahami | 0:47 A photographer recounts the moment he witnessed the arrest of NYC bombing suspect Ahmad Khan Rahami, after a shootout in New Jersey. 10 of 25 Skip in Skip x Embed x Share CLOSE EXPLOSION IN CHELSEA NEIGHBORHOOD OF NEW YORK CITY Suspected N.Y., N.J. bomber taken into custody | 0:36 Ahmad Khan Rahami, the suspect wanted in connection to the New Jersey and New York City bombings, is now in custody. (Sept. 18) AP 16 of 25 Skip in Skip x Embed x Share CLOSE EXPLOSION IN CHELSEA NEIGHBORHOOD OF NEW YORK CITY Mayor calls New York City explosion a bombing | 1:00 New York City's Mayor Bill de Blasio says an explosion that rocked a Manhattan neighborhood Saturday night was caused by a bomb. "However, when the binary components are combined, the resulting mixture is an explosive material," the ATF warned. In response to the Chelsea explosion, Tannerite Sports said it is working to determine if their product was definitely used in Saturday’s explosion.
– A legal product that can be purchased online or at a sporting goods store was used in the bomb that went off in Manhattan Saturday, USA Today reports. Tannerite is a product typically used for target practice; it is placed on targets and explodes when struck by a bullet from a high-powered rifle. It's sold in two inert parts (ammonium nitrate and aluminum powder), neither of which is regulated by the ATF. Once those two parts are mixed together, it only explodes if a bullet hits it and is considered very stable, a corporate investigator for Tannerite says. Tannerite residue was found inside the bomb that exploded in Chelsea, a federal law enforcement official tells USA Today. A post on the company's Facebook page Monday reads, "The entire staff of Tannerite stands together in the abhorrence and unintended use of all products that are misused for violence and hate." It goes on to note that its investigator is working to verify that Tannerite was indeed used in the bomb. A former FBI agent tells CBS News Tannerite appears to be "on the defensive." "It’s just something we have to be aware of that these terrorists are very clever at finding out what components can come together and make an improvised exploding device," he says. Forbes has more on the science behind Tannerite.