"I considered this a homeland security issue and I can envision this being a real problem for law enforcement someday," Merritt said.
Few federal restrictions
Exploding targets consist of ammonium nitrate (an oxidizer) and aluminum powder (a fuel). But because neither component individually is explosive, they not regulated by the Bureau of Alcohol, Tobacco, Firearms and Explosives.
Once the components are mixed, the results is an explosive material and subject to ATF regulations.
However, under federal law, individuals can manufacture explosives for their own personal, non-business use. There is no federal limit on the amount of explosives an individual can make.
Federal law, in short, does not prohibit exploding targets.
But, federal officials say, federal law does regulate the manufacture of explosive devices, and federal laws could be used to prosecute individuals who use the targets in the construction of explosive devices. The intent of the individual is a factor in determining legality, officials said.
Some state and local governments have taken action against sports shooters, especially in cases in which they've mixed large volumes of the target ingredients.
In the case of Brian Childs, the Minnesota man who shot at the 100 pounds of Tannerite in the dump truck, prosecutors viewed the truck not as a target, but as a bomb.
"It looks like they legally bought (the components). It was shipped to them by the Tannerite people," said Chris Schrader, assistant county attorney for Goodhue County.
But when the components were mixed and placed in the dump truck, "we looked at our definition of an explosive device and it definitely qualified," Schrader said.
"It was how they used it, which was enormously dangerous and ill-conceived," Childs said. "It was enormously reckless how they were using it. They had no idea what they were doing and you can tell by their reaction (in a videotape of the incident)."
According to a police report, a large piece of metal flew over Childs head, even though he was 300 yards from the blast.
Tannerite Sports, the Oregon-based manufacturer of the most popular brand of explosive targets, said it is being harmed by the widespread misuse of the product. And by people wrongly claiming that other products are "Tannerite."
"You can Google all day long and the first thing that will be popping up, people will be misusing our product and other products, other brands of binary exploding targets. It's a misuse," said Dena Woerner, a publicist for Tannerite Sports.
"Our produce was created to be used as a shot indicator. With Tannerite, you can see if you actually hit your target without having to walk down the range. And when you misuse a product, you could potentially be breaking the law."
The rampant misuse of exploding targets is a "threat to our business," Woerner concedes, so much so that the company is now soliciting videos of people using the product as intended.
"If people get hurt they're going to be more regulations and restrictions. We want people to be able to have fun with the product ... if they keep misusing it, people may not have that liberty anymore."
But federal officials take issue with Tannerite's claims that their product cannot result in fires.
At a press conference announcing the ban on exploding targets in certain national forests, it released a video showing a bale of hay catching fire after an exploding target was shot. The target was Tannerite, said Forest Service spokesman Lawrence Lujan.
Lujan said other brands also cause fires, and the Forest Service is likely to extend its ban to other regions.
A big bang
At a farm on Maryland's Eastern Shore, bomb squad member Matt Wrenn takes aims a Winchester rifle at targets at a range bounded by soybean fields, woods and an earthen berm.
He flawlessly shoots at a series of targets set up to demonstrate the fire marshal's concerns about exploding targets.