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Exploding targets ignite wildfire debate


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Evidence of an exploding target found at the origin point of a previous wildfire. The investigation of the fire has been completed. | Idaho Falls District BLM

IDAHO FALLS — Exploding targets have caused five separate wildfires in eastern Idaho just this month, federal fire investigators say.

But there still seems to be some confusion locally about whether or not exploding targets actually ignite wildfires. has received a great deal of feedback and correspondence this month from readers doubting Bureau of Land Management’s analysis of the fires.

Here’s what we found out.

Recent fires and investigations

In the last month, we’ve seen the Lava Rock, Liberty, North Butte, Cinder Butte and Badger Point Fire all started due to exploding targets.

While all of the cases are under investigation, we know the most recent fire on July 22 — the Badger Point Fire — was caused by exploding targets because BLM tracked down the responsible parties and charged them with misdemeanors. has requested all investigative reports related to these fires but we have been told the investigations will take several months to complete.

“We usually get one or two of these fires a year,” Idaho Falls District BLM Fire Mitigation and Education Specialist Kevin Conran told “It seems like this year, we’re getting more of them.”

So far, 532 wildfires have burned in Idaho this year. Eastern Idaho has had 56. Of those, 27 were caused by lightning, and 29 were caused by humans.

Conran said investigators work to discover the cause of each new wildfire.

Evidence of an exploding target found at the origin point of a previous wildfire. The investigation of the fire has been completed. | Idaho Falls District BLM

“We interview witnesses and first responders to try to narrow our search area,” Conran said. “When a fire passes through vegetation or other materials, it leaves burn patterns that we can observe and interpret and trace the fire back to the area of origin.”

Once investigators believe they are near the point of origin, they look for evidence of what started the fire.

“In the instances of exploding targets, sometimes that evidence is part of the container that the exploding target was in,” Conran said. “Sometimes we can still read the labels on them.”

Although there are a variety of types and brands of exploding targets, the most popular kind — which can be purchased at most department stores — are binary exploding targets. These targets use ammonium nitrate and aluminum powder. Once the two substances are mixed, they become explosive.

Conran said they will find evidence that shooting was going on, and sometimes they can even find traces of the white, ammonium nitrate pellets used in binary exploding targets.

“Sometimes the people who shot the exploding target will stick around and tell us that’s what happened,” Conran said.

The debate around exploding targets

Many online forums and Youtube videos suggest exploding targets — especially those produced by Tannerite — will explode, but are not flammable and will not start forest or wildfires. After published recent articles on wildfires, some readers insinuated the BLM is not being truthful about the cause of these wildfires. reached out to Tannerite to find out if its products are, indeed, incapable of starting fires. The spokesperson only said the company’s products “are not designed to start fires.”

The debate generally centers around how the chemicals in the exploding target are mixed.

An exploding target that causes a fire.

Research into exploding targets

The Missoula Fire Sciences Laboratory in Montana began studying exploding targets and how they start wildfires in 2014. Research scientist Dr. Mark Finney, the principal investigator, said he hopes to finish the study by the end of the summer.

He said the study indicates the aluminum in exploding targets is responsible for starting fires. Aluminum is also a common substance found in fireworks and sparklers. Aluminum burns at 4,532 degrees and it only takes 572 degrees for grass to catch on fire,

“If you have exactly the right amount of aluminum and ammonium nitrate under ideal conditions, perfectly mixed, it’s supposed to detonate,” Finney said. “There’s a fireball associated with the detonation, but that doesn’t last very long. Most of the aluminum is consumed, and most of the ammonium nitrate is consumed in the detonation.”

He said a fireball created by a perfectly mixed and perfectly detonated exploding target can cause a fire, but the real danger comes from an exploding target that was not properly mixed or was only grazed by the bullet, causing the target to only partially detonate.

“If you have an incomplete detonation, you increase the amount of aluminum that’s ejected from the blast zone in a burning condition,” he said. “It’s not detonating — it’s burning.”

A quick YouTube search uncovers numerous videos showing exploding targets starting fires among the countless videos of people successfully using exploding targets for recreational shooting.

An exploding target that doesn’t start a fire.

Finney said even regular target shooting can start fires.

“Exploding targets are one means by which target shooting can result in ignitions for wildfires,” he explained. “A lot of target shooters don’t know that just regular ol’ bullets smacking into a rock or a steel target can heat up enough to ignite vegetation.”

A 2013 study by the U.S. Forest Service found that even lead-core bullets can cause fires, though that is a rare occurrence. Lead does not heat up as much as solid copper, steel-core or steel-jacketed bullets.

Exploding targets are prohibited on public lands between May 10 and Oct. 20, as well as incendiary, steel core or tracer ammunition.

“Yes, they can definitely start fires and they do start fires,” Finney said. “There’s no question about it.”