If you watch any movie or television show, one aspect of hazardous materials that is constantly overdone is DOT Hazard Class 1 – Explosives. The smallest amount of explosives will produce the biggest bang, the loudest boom, the largest fireball and the biggest amount of damage this side of a nuclear device. As with anything we see on the big and small screens relating to emergency services, we must take what we see with a skeptical eye. Explosives in any amount can be extremely dangerous, but very rarely do they produce the effects that Hollywood likes to portray. Let’s take a look at explosives in this installment.
It is easy for any First Responder to identify explosives. They are the only placard with an orange background color. The hazard class (1) or any of the sub-classes (1.1, 1.2, 1.3, 1.4, 1.5 or 1.6) will be in the bottom corner. The “explosion” icon will be in the top corner. Please keep in mind that an explosive placard will be found on shipments containing an explosive material — such as ammonium nitrate — or on shipments containing explosive devices — such as bombs or missiles).
It should be noted that the DOT Emergency Response Guidebook utilizes Guide Numbers 112 and 114 all explosive materials and devices. DO not allow this fact to lull you into a false sense of security. ALL explosive materials have the ability to kill you! Do not underestimate Class 1.6 because it is the lowest class. It will kill you just the same. The only difference between death caused by a 1.1 explosive and death caused by a 1.6 explosive may be how much of the victim is found after the blast. That may sound a bit melodramatic but it is the truth.
Materials classified as 1.1 are considered to be a mass detonation hazard. If one portion of the shipment should detonate it could very well affect the entire shipment, causing the rest of the explosive material to detonate as well. These explosives are often considered as “high explosives” where the shock wave after detonation travels faster that the speed of sound. Examples of Class 1.1 materials include the explosives known as TNT, RDX, and PETN to name a few. Other examples of Class 1.1 materials include bombs, rockets and detonators.
Materials classified as 1.2 are considered to be materials that have a projection hazard, but not a mass detonation hazard. If one portion of the shipment were to detonate, it would generate a blast wave and shrapnel, but it would not cause the entire load to detonate like in the case of materials classified as 1.1. Fireworks, flares and smoke grenades are just some of materials classified as 1.2.
Materials classified as 1.3 are materials that have a mass fire hazard with a limited blast or fragmentation hazard. Hazard class 1.3 presents more of a fire hazard than it does a blast hazard. This does not mean that firefighters can drop their guard here. This is not a fire like a structure fire or a car fire. There is a limited fragmentation hazard, not a non-existent one. If one portion of the shipment were to catch fire, it could easily spread to the rest of the shipment or combustible materials located close by presenting a mass fire hazard. Examples of 1.3 materials include solid and liquid rocket propellant, flash powder and fuses.
Materials classified as 1.4 are materials that have a moderate fire hazard with no blast or fragmentation hazard. Any explosive effects are limited to the shipping package itself. For safety’s sake, assume there will be some fragmentation, but it will not be nearly as severe as the previously discussed classes. Examples of 1.4 materials include small arms ammunition, detonator cord, model rocket motors and smoke signals.
Materials classified as 1.5 are known as blasting agents such as ammonium nitrate. These materials are rather insensitive requiring a ignition chain to detonate the main charge. For example, it requires a blasting cap to detonate a stick of dynamite to detonate the main charge of ammonium nitrate. Materials classified as 1.5 have a mass explosion hazard but present a relatively low hazard during transportation due to the nature of the material.
Materials classified as 1.6 materials that are extremely insensitive that do not have a mass detonation hazard. These materials are less dangerous than materials classified as 1.5 in that they have an even less change of accidental detonation or ignition. One of the more common 1.6 materials are “squibs” or the small explosive charges that Hollywood uses to simulate gunfire or other small explosions. Stunt people and actors have been injured and even killed because they did not respect the power of the explosive charge. We all need to learn from their mistakes and give this hazard class the respect that it demands and deserves.
In closing, let’s remember one thing about explosives. Even though they are classified by the Department of Transportation and even though DOT Hazard Classes are taught as part of Hazardous Materials Operations and Technician courses, very few fire service personnel are schooled in explosives and even fewer can be classified as “experts”. The real experts when it comes to dealing with explosives (either explosive materials or explosive devices) are the bomb technicians in law enforcement and the military. Do not hesitate to call for their expertise if you are ever faced with an explosive of any kind. Their knowledge and response could literally mean the difference between life and death. If you ever have the opportunity to take a class or do some cross training with bomb technicians, please do so. I guarantee you won’t be sorry.
Until next time, remember that everyone needs to go home and go home well. Stay safe!