On June 30, the Los Angeles Police Department detonated fireworks in a containment vessel mounted on a vehicle. The resulting blast damaged cars and houses and injured people. Sahra Sulaiman has been covering the blast and subsequent events. She has summarized the events around the blast.
I’m always intrigued by reports of explosives gone wrong. I worked with scientists in the explosives division of the Los Alamos National Laboratory, in their laboratories, on a chemistry project that did not involve explosives. In order to do that, I had to have training on explosives safety. Additionally, because people who decide to make their career in explosives love explosions, I was invited to observe a number of explosions.
The early reports of how the LAPD bomb technicians had prepared the explosives for destruction in the containment vessel concerned me. The vessel had a limit on the size of explosion it could safely contain and thus on the amounts and kinds of explosives. The information in those reports suggested to me that the bomb technicians were not trained well in multiple ways.
Now the LAPD has released their after-action report and a report from the federal Alcohol, Tobacco, and Firearms Bureau on their investigation of the blast.
The overall conclusion is that the LAPD bomb technicians calculated incorrectly the effective weight of explosives and overloaded the vessel. Their training was inadequate. The reports do not go into detail on what the training has been or should be. Let me make a few suggestions from my experience.
The primary fact that all training and safety precepts flow from is
EXPLOSIVES ARE DANGEROUS MATERIALS THAT CAN KILL AND MAIM
As I read the reports, it was hard to see this as the underlying current of logic. The emphasis was on bureaucracy. Even though bureaucracy can be long on procedure, the reports put little emphasis on procedure, which is essential for safe operations with explosives.
Essential procedures would include
- Placards on the vessel structure with necessary information about its limits and use.
- Checklists for technicians and supervisors
- Requirements for double-checking of calculations
- Provision of a scale in the vehicle to measure explosives
- Placards listing explosive content of common fireworks.
Training should include when to estimate and when to weigh, along with best practices for estimation. My rule of thumb for something the size of a soda can, as many of the mis-estimated fireworks were, is that it would weigh about a pound. The bomb tech estimated one and a half ounces. An estimate of a pound would have been too high, but it wouldn’t have blown the vessel.
The countercharge – which, I derive from context, is the amount of explosive necessary to detonate the confiscated explosives – was also calculated incorrectly. The amount used seemed high to me, but there should be instructions and a checklist to match the countercharge to the materials to be destroyed. The reports do not mention instructions or a checklist.
Communications among the team seem to have been casual, and members seem to have questions they felt they could not ask. Here’s another basic precept for dealing with explosives:
ALWAYS ASK IF SOMETHING SEEMS WRONG TO YOU
Finally, the safety of the people involved is primary. Numbers in the immediate vicinity of the explosives should be minimized, and others should remain at a safe distance. This should also be part of a checklist. Moving spectators back from the vehicle seems to have been an afterthought.