Post Blast

By Doug Bleeker

Doug Bleeker is a Deputy Chief with Spokane County Fire District 9 where he oversees the fire investigation team. He has 21 years in the fire service and has been an investigator since 1994. Doug served three years on the board of directors for the Washington Chapter of IAAI and currently chairs Region 9‚s Fire Investigation Committee.

NFPA 921 includes some information on explosion investigation in chapter 21. So we have a little guidance to how an explosion investigation should be performed. Few of us have much experience in explosion investigation however. We just don’t have enough things blowing up here in the northwest for local fire agencies to develop in- depth skills in post-blast analysis. Obviously this is an area where neatness counts. Inattention to even the smallest detail can negatively impact one’s career.

This May, at the state conference, a group of experienced experts from Bureau of Alcohol, Tobacco, Firearms and Explosives offered some in-depth training to help fire investigators fine-tune their approach to post-blast explosion investigation. Explosive Enforcement Officer Phil Whitley was aided by his partner Brennan Phillips and others to introduce fire investigators to some important aspects of explosion examination.

Whitley pointed out that our standard fire investigation techniques and skills give us a good basis to begin with for explosion investigation and he expanded from those skill sets. The course looked at a standard list of questions any explosion investigation should seek to answer. We studied chemistry and characteristics of common industrial explosives. Activation systems and components were explained. The mechanics of explosions were outlined. Timing device design was explored. Components of explosive devices were examined both before detonation and after to show investigators what these components will look like at a post-blast scene. We also compared and contrasted industrial explosive applications with illegal explosive applications. Obviously the two differ greatly and the prudent investigator needs to be aware of these differences.

Students were led through real-world case studies of bombings, investigations and prosecutions to get a feel for how bombers and do-it-yourself pyrotechnic aficionados think and design their devices. Several very recent case studies taken from the northwest were examined. Many of them raised concerns, and eyebrows, regarding the hazards that are being built in garages across the northwest. The three most common illegal devices that the Seattle BATFE office sees are:
1. pipe bombs,
2. remanufactured hand grenades (they showed us some do-it-yourself kits that would amaze you), and 3. flash powder devices, used mostly in the illegal fireworks trade.

On the last day of class, a team of instructors detonated samples of the major industrial explosives so students could get a feel for how each explosive behaves. Several different activation components were demonstrated. A number of home-made explosive and pyrotechnic components were detonated to give us a feel for how dangerous these items can be.

In the final portion of the class, four different explosive devices were detonated and the class was divided into teams to analyze each scene, reconstruct the device and report back to the class on findings. Each device was based on a real-world incident that BATFE had investigated. Just like poking through burn cells in your basic fire investigator class, these examples gave students experience in what to look for and how post-blast bomb components will look. We all got a better feel for how much we can expect
to reconstruct in different explosion scenarios.

As we see more disenchanted political activists and junior chemists with nothing better to do, the skills taught in this course will become more important to fire investigators across the northwest. In the end, Phil Whitley said that his purpose was to build students’ confidence in their ability to reconstruct what happened and prove that post-blast investigation can be done. It just needs to be done CAREFULLY!