California Department of Forestry and Fire Protection officials tried to create an “ember bomb,” following a method advised by Inspire, a magazine published by terrorist group al-Qaida in the Arabian Peninsula. They found the method impractical for starting wildfires, an official document says.California Department of Forestry and Fire Protection

When a publication that advocates terrorism instructed readers earlier this year to use so-called “ember bombs” for setting off destructive wildfires, officials from the California Department of Forestry and Fire Protection decided to test the attack strategy. It’s not all that practical, they concluded after experiments conducted in May. 

Arson experts wrote up their findings in a June document marked “for official use only” and distributed through the California State Threat Assessment Center. The memo was leaked onto the Internet and found its way to the WikiLeaks-style government transparency site Public Intelligence.

California officials took their idea from a magazine that al-Qaida in the Arabian Peninsula began publishing two years ago called Inspire, designed to spread the group’s message and attract recruits. The latest issue, published May 2 – the first since a U.S. drone strike killed al-Qaida propagandist Anwar al-Awlaki in September – contained articles sketching out the history of forest fires and urging readers to build firebombs and use them to spark blazes.

One article curiously claimed that Montana was the best target for such an attack.

“In America, there are more houses built in the (countryside) than in the cities,” Inspire reportedly wrote. “It is difficult to choose a better place (than) in the valleys of Montana.”

Wanting to determine if the bomb actually would work, California fire officials took a plastic water bottle and cut it in half. They then filled the bottle with gasoline, adding Styrofoam until the substance took on a gelatinous consistency.

They first tried to ignite it using the method advised by Inspire, with a 9-volt power supply, timer and match heads placed inside a broken lamp taped to the lid of the bottle. That didn’t work well enough, so it was manually ignited with a match instead. Once ablaze, the device burned for nearly 12 minutes.

“At no point during the test were embers produced,” according to the document. “The device concentrated heat in one location. … The device remained only a localized heat source, and because of this, there appears to be little practicality associated with employing this method versus others that would likely leave far less physical evidence, such as manually starting a burn with a cigarette lighter.”

If any would-be terrorists do attempt an “ember bomb,” the memo says, they likely will test it first and possibly leave behind evidence of wires and a burned-out lamp. Several photos of the test were included and show the low-intensity burn producing a plume of black smoke.

The intelligence document also provides a background of Inspire and past incendiary devices the magazine has described in a regular feature called “Open Source Jihad.”

“The (feature), which began with the first issue in 2010, includes articles describing the practical application of terrorist tactics, techniques and procedures. One of the first articles, entitled ‘Make a bomb in the kitchen of your Mom,’ provided step-by-step instructions for constructing a pipe bomb. Other topics have included the proper methods for employing an AK-47 type weapon, operational planning consideration and how to establish secure electronic communications.”

G.W. Schulz is a reporter for Reveal, covering security, privacy, technology and criminal justice. Since joining The Center for Investigative Reporting in 2008, he's reported stories for NPR, KQED, Wired.com, The Dallas Morning News, the Chicago Tribune, the San Francisco Chronicle, Mother Jones and more. Prior to that, he wrote for the San Francisco Bay Guardian and was an early contributor to The Chauncey Bailey Project, which won a Tom Renner Award from Investigative Reporters and Editors in 2008. Schulz also has won awards from the California Newspaper Publishers Association and the Society of Professional Journalists’ Northern California Chapter. He graduated from the University of Kansas and is based in Austin, Texas.