Researchers analyze wildfire ignition with almost 100 tests of exploding targets

Exploding targets have ignited numerous wildfires and are banned in many areas

Above: Figure from “Experiments on Wildfire Ignition by Exploding Targets”, by Mark A. Finney, C. Todd Smith, and Trevor B. Maynard. September 2019.

Researchers with the U.S. Forest Service and the Bureau of Alcohol, Tobacco, Firearms and Explosives detonated almost 100 exploding targets to gather information about how likely they are to ignite a wildfire.

Exploding targets consist of two ingredients that when mixed by the end user explode when shot by a gun. They have caused many fires since they became more popular in recent years, have been banned in some areas, and caused the death of at least one person. In 2017 an exploding target started what became the 46,000-acre Sawmill Fire southeast of Tucson, AZ. After the ingredients are combined, the compound is illegal to transport and is classified as an explosive by the Bureau of Alcohol, Tobacco, Firearms, and Explosives.

The tests were carried out in 2015 and 2018 by shooting a high powered rifle at the targets — 46 tests in 2015 and 51 in 2018. The results could not have been more different in the two batches of tests. There were no ignitions of the nearby straw bales from the exploding targets in 2015 (zero percent), but there were 22 in 2018 (43 percent). The weather conditions made the difference. In 2015 the temperature was 31 to 46 and the relative humidity was 64 to 99 percent. During the 2018 experiments the temperature was 71 to 82 and the relative humidity ranged from 14 to 23 percent, conditions much more conducive to ignition of vegetation.

Experiments on Wildfire Ignition by Exploding Targets
Data about exploding target tests in 2015 and 2016. From “Experiments on Wildfire Ignition by Exploding Targets”, by Mark A. Finney, C. Todd Smith, and Trevor B. Maynard. September 2019.

The experiments in 2018 were carried out with 5.56×45 mm ammunition, which is used in some AR-15 rifles.

The researchers’ findings can be found in “Experiments on Wildfire Ignition by Exploding Targets”, by Mark A. Finney, C. Todd Smith, and Trevor B. Maynard. September 2019. (7.3 MB file)

The most common ingredients of exploding targets are the oxidizer ammonium nitrate (AN) and for fuel, aluminum powder (AL). Commercially available exploding targets have various concentrations of aluminum which is what actually burns during the explosion, which generates temperatures of about 6,700 °F.

The testing showed a direct relation between the aluminum content of the products and the prevalence of ignition and visible burning aluminum in the explosion.

The AL content of the target mixture had an effect on ignition of the straw bales:

The popularity of these products has led to a wide range of formulations to include more rimfire products that rely on increased metallic fuel content for sensitivity. The testing did show a direct relation between the aluminum content of the products and the prevalence of ignition and visible burning aluminum in the explosion. Wildland fire investigators considering an exploding target hypothesis for a fire start should be aware of the range of products available and how aluminum content, mixing, and other variables might impact the performance of the product and the likelihood of ignition. Tannerite is one of the most common commercial brands of exploding target, but with only approximately 1.6 percent AL, it is among the least likely to cause ignitions compared to brands or formulations with higher AL concentration.

During the tests in 2018 researchers used mixes with AL ranging from 1 to 10 percent.

Some of the first exploding targets had to be shot by a high-velocity projectile fired from certain center-fire rifles. Variants are now available that can be shot by rimfire cartridges (e.g., .22 Long Rifle) or pistols. These targets rely on a greater percentage of AL or other ingredients to increase sensitivity to initiation. Rimfire targets have been found with up to 25 percent AL.

The researchers had some tips for fire cause and origin investigators:

Informal observations during this research suggested that the use of exploding targets may leave evidence in and around the blast seat. The research team observed some shattered pieces of the plastic containers in and around the blast seat following testing. This plastic, which exhibited exposure to high temperatures, appeared to have embedded AN on one side of the plastic. The team also observed unconsumed AN prills on the ground around the blast seat during testing. While this in no way means such evidence is present after all exploding target explosions, fire investigators should be cognizant that potential forensic evidence may be located around the blast seat that should be collected and documented.

In addition to documenting physical evidence that can aid investigators, another thing this research accomplishes is it makes it easier to prosecute cases where a defendant is accused of starting a fire by shooting at an exploding target. It proves that the devices CAN start a fire. Prior to this, an attorney might argue, exploding targets do not ignite fires.

Thanks and a tip of the hat go out to LM. Typos or errors, report them HERE.

Investigators determine wildfire near Helena was started by exploding target

A suspect has been cited and may have to pay suppression costs

North Hills Fire Helena exploding target
Investigators determined that the North Hills Fire was started by an exploding target on July 26, 2019.

Investigators have determined that the North Hills Fire that burned 5,005 acres 10 miles northeast of Helena, Montana was started by a Tannerite exploding target July 26, 2019.

Below is an excerpt from an article in the Independent Record:

Two citations were filed Thursday against the person suspected of starting the North Hills fire that burned more than 5,000 acres near Helena earlier this summer.

U.S. Bureau of Land Management law enforcement cited the suspect with one count of causing a fire other than a campfire and one count of burning timber, trees, slash and brush outside of a campfire. Each ticket carries a $500 fine plus a $30 processing fee for a total cost of $1,060.

The citations do not include the costs associated with suppressing the wildfire or rehabilitating the burned area. Any possible civil action will be handled administratively by the agencies involved.
The Montana Department of Natural Resources and Conservation has estimated the suppression costs “somewhere in the neighborhood of $7.2 million,” according to Helena Unit Manager John Huston.

“We probably will go after some suppression costs,” he said, noting that the process would probably take about a year.

Local and federal officials have declined to release the suspect’s name.

The North Hills Fire forced the evacuation of 400 homes northeast of Helena.

Walt Jester, Chief of the Lewis and Clark Volunteer Fire Department, took some excellent photos of the fire:

Exploding targets consist of two ingredients that when mixed by the end user explode when shot by a high-velocity projectile. They have caused many fires since they became more popular in recent years, have been banned in some areas, and caused the death of one person. After the ingredients are combined, the compound is illegal to transport and is classified as an explosive by the Bureau of Alcohol, Tobacco, and Firearms.

Thanks and a tip of the hat go out to Paula. Typos or errors, report them HERE.

Photos during tests of exploding targets

(Above: photo by Idaho State Fire Marshal’s Office)

During the last week of August, the Idaho State Fire Marshal’s Office, along with other experts and investigators from around the Pacific Northwest participated in scientific testing of exploding targets and their propensity for igniting wildfires in the forest environment.

Thanks and a tip of the hat go out to Steve. Typos or errors, report them HERE.

Forest Service releases video of explosion that started 46,000-acre fire

A U.S. Border Patrol agent pleaded guilty to starting the Sawmill Fire southeast of Tucson by shooting at an exploding target

The U.S. Forest Service has released a video of the exploding target that started what became the 46,000-acre Sawmill Fire southeast of Tucson in 2017.

Border Patrol agent Dennis Dickey has pleaded guilty to starting the fire. He was holding an off duty party to celebrate his wife’s pregnancy at which the gender of his baby was revealed. He mixed colored powder into a Tannerite exploding target which would show blue or pink smoke when shot with a rifle. The target exploded as planned, revealing the blue powder, but it started what became the Sawmill Fire. A witness recorded video of the explosion.

exploding target starts fire wildfire
A screenshot from the video below showing the exploding target that started what became the 46,000-acre Sawmill fire.

Agent Dickey set up the dangerous device at a location where it was surrounded by dry grass and mesquite trees. At the end of the video a voice can be heard shouting twice, “Start packing up!”.

The video obtained by the Arizona Daily Star from the U.S. Forest Service through the Freedom of Information Act  is below.

One of the commenters where the video is posted on YouTube, wrote, “I feel bad for the poor baby boy who’s inheriting those genes.”

Agent Dickey said he attempted to put out the fire but when that failed, he reported it. At one point during the next week at least 799 firefighters were working to put out the fire, which ran up costs of approximately $8.2 million according to the May 5, 2017 national Situation Report.

On April 23, 2017, the day the fire started, the Hopkins weather station not far from where the fire began near Madera Canyon, recorded a high temperature of 80 degrees, 11 mph WSW winds gusting to 25, and 6 percent relative humidity. The weather station is at 7,100 feet and the location of the party where the fire started is most likely around 4,000 feet. If correct, this would put the temperature at the fire origin between 90 and 100 degrees.

news release from the U.S. attorney’s office said Agent Dickey will make an initial payment of $100,000, then make monthly payments after that. According to the Arizona Daily Star and the Green Valley News, he agreed in court to pay $500 a month for the next 20 years, which adds up to $120,000, for a total of $220,000 including the first payment. He also will be sentenced to 5 years of probation and agreed to participate in a public service announcement with the U.S. Forest Service concerning the cause of the Sawmill fire.

Exploding targets consist of two ingredients that when mixed by the end user explode when shot by a high-velocity projectile. They have caused many fires since they became more popular in recent years, have been banned in some areas, and caused the death of one person. After the ingredients are combined, the compound is illegal to transport and is classified as an explosive by the Bureau of Alcohol, Tobacco, and Firearms.

Border Patrol agent pleads guilty to starting 46,000-acre fire with exploding target

A Border Patrol agent pleaded guilty Friday to starting the Sawmill Fire that burned 46,000 acres southeast of Tucson, Arizona in 2017. Dennis Dickey was holding an off duty party to celebrate his wife’s pregnancy at which the gender of his baby was revealed. On April 23 he mixed colored powder into a Tannerite exploding target which would show blue or pink smoke when shot with a rifle, according to his attorney, Sean Chapman, as reported by the Arizona Daily Star. The target exploded as planned and started what became the Sawmill Fire. A witness recorded a video of the explosion.

A news release from the U.S. attorney’s office says Agent Dickey will make an initial payment of $100,000, then make monthly payments after that. According to the Arizona Daily Star and the Green Valley News, he agreed in court to pay $500 a month for the next 20 years, which adds up to $120,000, for a total of $220,000. He also will be sentenced to 5 years of probation and agreed to participate in a public service announcement with the U.S. Forest Service concerning the cause of the Sawmill fire.

The off-duty agent could not be charged with arson since it was not a willful act. He pleaded guilty to a misdemeanor charge of causing a fire without a permit, which may allow him to keep his job as a Border Patrol Agent.

Agent Dickey said he attempted to put out the fire but when that failed, he reported it. At one point during the next week at least 799 firefighters were working to put out the fire, which ran up costs of approximately $8.2 million according to the May 5, 2017 national Situation Report.

satellite map Sawmill Fire Arizona
A satellite photographed the darkened outline of the Sawmill Fire east of Green Valley, Arizona on April 26, 2017. The red dots represent heat.

On April 23, 2017, the day the fire started, the Hopkins weather station not far from where the fire began near Madera Canyon, recorded a high temperature of 80 degrees, 11 mph WSW winds gusting to 25, and 6 percent relative humidity. The weather station is at 7,100 feet and the location of the party where the fire started is most likely around 4,000 feet. If correct, this would put the temperature at the fire origin between 90 and 100 degrees.

In court, Agent Dickey told the judge, “It was a complete accident”.

Exploding targets consist of two ingredients that when mixed by the end user explode when shot by a high-velocity projectile. They have caused many fires since they became more popular in recent years, have been banned in some areas, and caused the death of one person. In June, 2013 a man attending a bachelor-bachelorette party in Minnesota was killed after shrapnel from the device struck him in the abdomen. The Missoulian reported that several years ago a woman in Ohio had her hand nearly blown off while taking a cellphone video of a man firing at an exploding target placed in a refrigerator about 150 feet away. In Georgia in 2016 David Pressley’s leg was blown off by an exploding target that he placed in a lawn mower.

After the ingredients are combined, the compound is illegal to transport and is classified as an explosive by the Bureau of Alcohol, Tobacco, Firearms, and Explosives and is subject to the regulatory requirements in 27 CFR, Part 555.

Man faces charges for starting wildfire with exploding target in Colorado

These dangerous devices are banned in many areas and have started many fires in the United States

Above: Firefighters suppress a fire started by a person shooting at an exploding target southeast of Eagle, Colorado June 9, 2018. Photo by Eagle River Fire Protection District.

A man has been charged with 4th Degree Arson and Reckless Endangerment for allegedly starting a fire at an unofficial shooting range near Minturn southeast of Eagle, Colorado on June 9.

According to the Eagle County Sheriff’s office the fire was started by the use of an exploding target.

Thanks to green vegetation at the scene and the efforts of firefighters, the fire was suppressed while it was still fairly small. Most of the state of Colorado was under a Red Flag Warning Saturday. On the same day the Boco Fire burned about 400 acres a few miles away.

Exploding targets are known to have started numerous fires. In 2017 an off-duty Border Patrol agent shooting at an exploding target started what became the 46,000-acre Sawmill Fire south of Tucson, Arizona which cost at least $5 million to fight.

Exploding targets consist of two ingredients that when mixed by the end user create an explosion if shot by a high-velocity projectile. They have been banned in some areas, and in June, 2013 a man attending a bachelor-bachelorette party in Minnesota was killed after shrapnel from the device struck him in the abdomen causing his death. The Missoulian reported that several years ago a woman in Ohio had her hand nearly blown off while taking a cellphone video of a man firing at an exploding target placed in a refrigerator about 150 feet away.

After the ingredients are combined, the compound is illegal to transport and is classified as an explosive by the Bureau of Alcohol, Tobacco, Firearms, and Explosives and is subject to the regulatory requirements in 27 CFR, Part 555.

Articles on Wildfire Today tagged exploding targets.