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Mar 01, 2024

Recognizing Explosive Materials in the Fire/EMS Service, Part 2

An understanding of the “Fire Tetrahedron” is all a criminal needs to construct explosives. Jarred Alden on responding to improvised explosive devices. By JARRED R. ALDEN Unfortunately, an

An understanding of the “Fire Tetrahedron” is all a criminal needs to construct explosives. Jarred Alden on responding to improvised explosive devices.

By JARRED R. ALDEN

Unfortunately, an understanding of the “Fire Tetrahedron” is all a criminal needs to construct explosives. This is one reason first responders must understand how explosives are constructed, which includes knowledge of all components. Knowledge is power and safety in today’s violent world.

The Fire Tetrahedron’s components are a type of fuel, oxidizer, heat source, and chemical chain reaction. Fuels are usually carbon-based substances such as charcoal, sulfur, gasoline, wood, wax, pepper, cumin, and so on. Oxidizers could be bleach, pool shock, ammonium nitrate, potassium chlorate, and so on and have a suffix such as -ite, -ide, -ine, or -ate, included in the generic name. Heat sources come in many forms and can be mentally retained and recalled easily by using the acronym FISHED (Friction, Impact, Shock, Heat, and Electrostatic Discharge).

Explosives are broken down into the following categories:

For the purposes of this article, I will focus on high- and low-order explosives. I would be remiss, however, to fully omit a few examples of the other two categories. Dust-air explosions, which occur in grain silos, would be one example of a fuel-air explosion. Thermobaric weapons, which use the surrounding oxygen in the air to produce high temperatures, are another type of explosive (used by the Russian military and others). These explosives are also referred to as “aerosol” or “vacuum” bombs. Nuclear explosions are broken down into bombs that produce chemical reactions once one material mixes with another such as plutonium or uranium. The powerful reactions involved derive their destructive power and force from fusion, fission, or fusion-fission, depending on the type of nuclear bomb constructed. Atomic and hydrogen bombs are examples of nuclear explosives.

High-order explosives are interesting because they do not explode; therefore, the name given to these types of explosives is a misnomer. High explosives detonate because the solid changes to a gas in 1/1,000,000th of a second, and the explosive material is fully consumed. The detonation velocity will be more than 3,300 feet per second (ft/sec). Some high explosives will reach a detonation velocity of up to 27,000 ft/sec, such as C4 and a detonation cord. C4 is a shape charge because it is a mixture of the explosive material research development explosive (RDX) and a plasticizer, among other ingredients. The plasticizer allows for the material to be manipulated like putty. Detonation cords are used by SWAT teams to punch open doors because the energy is focused into one area. This cord is also used in the logging industry to knock down large trees, since wrapping detonation cord around a tree focuses the energy into the tree circumferentially, causing the tree to shear and fall. High explosives are rated by sensitivity to FISHED.

Primary high-order explosives are extremely sensitive and must be handled with great care. As stated above, some need to be stored in cooler environments and water to avoid detonation. Examples of primaries are TATP and blasting caps. Secondary high-order explosives are moderately sensitive to FISHED. Some examples are C4, RDX, Semtex, detonation cords, penthrite, and many others. RDX was invented by the Germans but was perfected by the British during World War II. Ironically, this material was used by the British during WWII to punch holes through German U-boats; the high energy caused enough damage to sink the boats. Tertiary high-order explosives have a very low level of sensitivity and need a major form of heat and shock to cause detonation. Examples of this category of explosive are ammonium nitrate fuel oil (ANFO), ammonium nitrate nitro methane (ANNM), urea nitrate, and nitro urea, to name a few.

TATP was used in the May 2017 Ariana Grande concert explosion in Manchester, England, by a suicide bomber, killing numerous people, including children, and injuring more than 1,000. The bombing of the Alfred P. Murrah building in Oklahoma City, Oklahoma, in April 1995 that killed and injured close to 850 people was done with ANFO and ANNM packed into numerous 50-gallon drums, which the bomber transported by a moving truck. He connected the drums with a detonation cord to produce the shock needed for the detonation. He then parked the truck outside of the building and walked to another vehicle, driving off. He was subsequently pulled over by a state trooper for not having a license plate. He was caught with a firearm and taken into custody roughly 80 to 90 miles from the bombing.

Low-order explosives have a detonation velocity of under 3,300 ft/sec. This type of explosive material needs to be contained to build pressure for an explosion to occur. Low-order explosive materials do not detonate if they are not fully encapsulated. Black powder is one example. Black powder will deflagrate, a rapid-burning process that produces heat, light, and sound. The explosive material will not be fully consumed after the blast. Materials can be sampled for analysis since powder residues are left over.

The material will need containment to build up pressure. The vessel will eventually fail, causing the explosion. The failure usually occurs at contact points that are weaker than the vessel such as where end caps are screwed onto a pipe; this is similar to a Boiling Liquid Expanding Vapor Explosion (BLEVE), which does not necessarily have to contain an explosive material.

Propellants used in firearms rounds and pyrotechnics used in fireworks are the subcategories of low-order explosives. Examples of both subcategories are black powders, smokeless powders, flash powder, and so on. Both high- and low-order explosive materials are usually nothing more than the mixture of a fuel and an oxidizer. There are other additives, such as hot fuels added for sensitivity, used in more sophisticated explosive materials and devices.

(1-3) Images from a fuel-air explosive event that occurred during a house fire in Akron, Ohio, on the C-shift. Akron Fire Department (AFD) Captain Greg Oziomek was functioning as Battalion #4. When he arrived on scene, Battalion #9 had already arrived and took command of the scene, which then designated him as incident commander. Oziomek assumed safety officer duties when he arrived on scene. While Oziomek was performing his 360° size-up, he walked up the driveway on the D side of the structure. Engine #6 had made entry through the same door and reported some fire in the threshold going to the basement. As this side door was breached and left open, the unilateral air entry gave the fire and ignitable liquid vapors in the house enough oxygen to cause an explosion. The side door leading to the driveway blew off the hinges and struck Oziomek, rendering him unconscious. He sustained broken bones in his right hand, a broken left elbow, a fractured left shoulder, and a fractured sternum. He also presented with two orbital fractures. Oziomek suffered one fracture to his maxilla and one fracture to his zygomatic. He sustained a bruised lung because of blunt-force trauma. Oziomek was diagnosed as also having retrograde amnesia, most likely from a concussion. His watch, portable radio, and pocket knife were all found roughly 30 to 40 feet behind him in the neighbor’s yard. Fire company members on scene found him underneath this door. He woke up in the hospital and could not recall responding to the incident or the explosion. (Photos courtesy of Greg Oziomek.)

When a bomb detonates or explodes (depending on the order of the explosive material), there will be an initial compression of air molecules. The air molecules will compress fast and with more pressure when a high-order explosive detonates. As the air pushes out from the seat of the blast in a 360° bubble, a shock front and an overpressure are produced. The shock front can and will cause damage to critical infrastructure, leading to full collapse and partial collapse of buildings. Communications capabilities may also become an issue if communications towers are pulverized or seriously damaged. A high-order explosive will also produce a blast wave, unlike a low-order explosive. This blast wave will cause hollow organ damage, especially to the lungs, intestines, bladder, tympanic membranes, and even the vascular system. Even though the vascular system has blood contained within the arteries, veins, and capillaries, the overpressures from the blast wave can travel into the vascular system and up into the brain, causing a twisting of the neurons in the brain’s tissue. This damage can lead to traumatic brain injuries and chronic traumatic encephalopathy. Collapse of pillars and beams onto casualties may lead to crush injuries, compartment syndrome, and crush syndrome.

The compression of the air molecules is mainly because of the rapid decompensation of the explosive materials and the high levels of heat produced. The levels of heat produced can reach up to 4,000°F or greater. This can cause fires that will require fire suppression from fire companies responding. Burns to victims’ airways, skin, and lungs will require medical responses to save lives such as intubation and cricothyrotomy interventions. Trauma hospitals and burn units must be equipped with the proper resources and be able to treat numerous patients all at once. This is idealistic thinking; therefore, incident commanders and safety officers must contact surrounding area hospitals to inquire about further resources and capabilities if the blast causes a mass-casualty incident.

Projectiles in the form of shrapnel and fragmentation are propelled 360° at high speeds; these velocities are close to a modern rifle bullet, which travels at 2,700 ft/sec. As these projectiles travel, they will tumble, rotating end-over-end, causing more serious tissue damage by creating wider entry and exit wounds, and yaw, wobbling and causing a wider entry and exit pattern in human tissue. In other words, the profile of the object is enlarged because of exaggerated movements regarding both effects. Damage to windows, buildings, cars, tanks, and people will occur. Penetrating trauma will be evident, leading to the need for quick interventions such as tourniquet placement, chest seals, and wound packing at junctions such as the neck, femoral and groin areas, the axillaries (armpits), and shoulders/hips. Extremity-specific tourniquets are not effective if placed in the junctions.

Projectiles moving at high speeds require a high level of shielding or cover, not concealment. The cover should be significant and strong enough to stop the projectiles. Finding cover behind a vehicle is not enough shielding; solid steel beams and concrete barricades and walls are the best cover. The best way to protect yourself and your crews is to have a great amount of distance between yourself and the seat of the blast. There are various distances suggested by the Federal Bureau of Investigation (FBI) and the Bureau of Alcohol, Tobacco, Firearms and Explosives, depending on the size of the container, vessel, or vehicle transporting the explosive device. For example, the FBI’s standoff card states to have a mandatory evacuation distance of more than 1,200 feet for a five-pound pipe bomb. Distance may be the only determining factor between life and death.

Another effect caused by an explosive postblast is the seismic effect, which refers to the 360° bubble that pushes out from the seat of the blast. The shock front, blast winds, and blast wave are partially absorbed into the ground. Most of these factors are reflected back into the air and into structures and people. As first responders, we must be cognizant of the possibility of a road collapse, especially if the bomb is placed on a bridge. Other factors with which we must be concerned are the structures under the road or ground. What kind of structures might be under the intersection of main roadways in large cities? In Akron, Ohio, beneath the intersection of Market and Main Streets lay large sewer and gas lines, electrical vaults, major cables, telephone lines and cables, and large water mains. If these utility structures were seriously compromised by an explosion, life as we know it would come to an abrupt halt. Major sections of our city would lose electrical power, gas for heating, water for drinking and bathing, waste removal capabilities, and communications capabilities. First responders would have to activate hazardous materials teams, decontamination teams, the Red Cross, the water department, state and federal agencies, and so on. What if we could not communicate with any other agencies or departments because of a compromise in our communications capabilities? There should be a backup communications plan in place. Incident command and safety officers must be familiar with these contingency plans.

(4-6) Shown here is a fuel-air explosion that occurred in Akron, Ohio, because of a natural gas leak. No samples of any ignitable liquids were found by investigators. The severe damage and full displacement of the roof and wall of this structure indicate that the natural gas had built up in the structure. The damage to the upper portions of the home and the roof indicates that the gas rose to the highest levels of the house. Natural gas is lighter than air; therefore, we can deduce that the gas moved to the upper portions of the house. The damage is visualized as the most damage to the structure, being from top to bottom. There was a tremendous pressure release during the explosion, causing the structure to “heave” outward. Photo 6 shows the location of the gas line leak, which caused some char on the wood. Once the fuel and air mixed to the correct level, all that was needed was a form of heat, which could have been any kind of friction, impact, shock, heat, or electrostatic discharge. The actual heat source was deemed “undetermined” by the AFD Investigations Unit. However, the dryer was running at the time of the explosion, and it was hypothesized that electric arcing or electrostatic discharge was the heat source. [Photos courtesy of the Akron (OH) Fire Department Investigations Unit.]

First responder activation and responses to these incidents can obviously be very dangerous. Although we are all sworn to protect and assist others in their time of need, we must also be cognizant of the fact that secondary and tertiary explosives may be close (or in close proximity) to the seat of the initial blast. Why would a bomber want to place more than one device? To cause more death and injury. Moreover, we can speculate, with a high level of probability, that the bomber wants to kill first responders. We may not be the initial targets, but if we are taken out of the picture, there is no order to the chaos; more lives will be lost if we are injured or killed. We cannot help others if we become casualties.

In an incident in Akron, an individual (or individuals) had placed an improvised explosive device (IED) on the railroad tracks in my battalion. The train companies had to be notified and that area of the track was shut down for hours so that the Summit County (OH) Bomb Squad could render the device safe. The initial first responder was one of our battalion captains, who investigated. I believe that whoever placed this device remained on scene, hidden to record our response times, rig placements, number of personnel, and the various responding government entities. Scene safety and situational awareness are paramount.

Blast injuries are broken down into five separate categories, which consist of the following:

Primary blast injuries. These are injuries sustained specifically from blast waves. Blast waves and blast winds are not the same and are solely from the aftermath of high-order explosives. For investigative purposes, if a casualty suffers from hollow organ collapse, failure, or damage, we can deduce that the explosive used was a high-order explosive. Low-order explosives are not powerful enough to cause internal injuries unless the injury is from a projectile. Low-order explosives will produce a blast wind but not a blast wave. Blast waves cause considerable changes in atmospheric pressures. Some blast pressures have been surmised to have risen to more than 600 pounds per square inch (psi) such as in the London subway bombings in July 2005. Tympanic membranes (ear drums) will rupture at a five-psi rise in atmospheric pressure, blast lung can occur at around a 25-psi rise in atmospheric pressure, and death will occur at a 100-psi rise in atmospheric pressure. Primary blast injuries can manifest as blast lung, pulmonary contusions, simple pneumothorax (leading to a tension pneumothorax), lung collapse, ruptured ear drums, intestinal perforations, bladder rupture, vascular compromise, and traumatic brain injuries such as chronic traumatic encephalopathy; these injuries are not all-inclusive, and the associated signs and symptoms may not manifest for many hours after blast exposure. With enough power from a blast wave, solid organs may crack and rupture as well.

Secondary blast injuries. Projectiles from flying debris such as fragmentation of the device will cause penetrating trauma. Shrapnel, which is added to the device to increase its lethality, will also cause the same or similar trauma. Fragmentation from objects other than the device, such as glass shards from windows, may be found inside of wounds. If the blast is powerful enough, then blunt-force trauma may result because of very heavy objects such as chunks of concrete being thrown by the blast wind and into a victim.

Penetrating injuries can occur anywhere on the body. The eyes have a very high probability of sustaining injuries. Extremity trauma will lead to major hemorrhage and full exsanguination if tourniquets are not applied properly.

I recommend placing tourniquets high and tight for two reasons. First, we may not be able to visualize all injuries to the extremities. We may have more trauma located higher on an extremity. Avoid tunnel vision, where your focus is on a distracting injury such as a missing hand; there may be more hemorrhaging occurring above that injury. The second reason for placing a tourniquet high and tight is rooted in basic anatomy and physiology. The arteries and veins traverse along the medial aspects of the long bones such as the humerus and femur. The arteries and veins traverse in between the radius and ulna of the lower arms and the tibia and fibula of the lower legs. It is much easier to compress vascular structures to one long bone than it is to tamponade these vessels, which are protected partially between two bones.

Junctional wounds should receive pressure dressings, hemostatic dressings, wound packing, and junctional devices. When packing a junctional wound, pack it up toward the heart if the wound is in the femoral areas and hold pressure with either hands or a knee. If the junctional wound is to the armpits or the sides of the neck/trapezius areas, pack the wound inward and down toward the heart, respectively. Truncal wounds will require a chest seal and possibly a needle decompression if a pneumothorax develops into a tension pneumothorax. If the medical provider runs out of chest seals, a good backup is a gloved hand and then place a defibrillation pad. This device will have to be burped, however. This method is a “last resort,” so be sure to follow your local protocols, policies, and procedures.

(7) This shows the aftermath of a low-explosive IED, which was placed on the threshold of the front door in between the solid core door and the screen door. The device was initiated, which blew the front door into the house and caused moderate damage to the walls and ceiling. The shock front and overpressures shattered glass in two other rooms. There was also glass inside and outside of the structure, which had shattered because of the reflective pressures and the negative pressures pulling compressed air molecules back to the seat of the blast. This was an investigation of someone who was being targeted. [Photo courtesy the Akron (OH) Fire Department Investigations Unit.]

Tertiary blast injuries. Blunt-force trauma is the most likely injury found and diagnosed within this category. These injuries may manifest as deformities to the skeletal structures, contusions, abrasions, lacerations, and so on because of the body being thrown into walls, into solid structures, and into the air only to drop back to the ground and other hard surfaces. Injuries to the skull, ribs, spine, and extremities are very common. Although hemorrhagic shock is very probable because of internal bleeding, neurogenic shock is also possible because of spinal cord damage. Moreover, maintain a high index of suspicion for internal brain hemorrhage such as epidural, subdural, and subarachnoid bleeding. A blown pupil with battle signs and “raccoon eyes” are serious indicators of basilar skull fractures.

Quaternary blast injuries. Crush injuries because of structural collapse are common during the aftermath of explosions. Collapse of heavy structures such as steel I-beams onto victims may lead to compartment syndromes and crush syndrome if the casualty is not extricated as soon as possible from the entrapment. If pinned for too long, the muscular damage will eventually develop into rhabdomyolysis. Be sure to initiate an IV or IO and administer sodium bicarbonate to attempt to counteract the effects of rhabdomyolysis prior to extrication if your local protocols indicate this intervention. This intervention is because rhabdomyolysis causes the muscles to release large amounts of by-products such as potassium into the vascular system, which will lead to cardiac arrest.

Another subcategory of injuries sustained in this category is thermal damage to the skin and structures of the airway. The number-one treatment for burns is to stop the burning process. Cool the burn with sterile water and place dressings over the burns. Procedures for burns change a lot, but stopping the burning process has remained as a treatment modality. Again, follow your local protocols when treating burns. IV or IO fluids are important to maintain hydration, but avoid initiating IVs and IOs in the burn areas.

Airway compromise is another major issue with burns because of the thermal effects of explosives. The airway and its structures are very delicate because of the soft inner tissues. Look for signs and symptoms of airway compromise such as soot on the face and tongue. Visualize the nares for burned nasal hairs. Be cognizant of burned or singed hair on the face as well. Wheezing, rhonchi, and rales are more ominous signs. Burns to the airway and lungs may lead to pulmonary edema and swelling of the airway, leading to closure of the airway, respiratory failure, and cardiac arrest. Intubation and cricothyrotomy procedures may be your only way to control airway compromise.

(8) The AFD’s thermal imaging meter used by the hazardous materials team and arson investigators to detect explosive materials and other substances. This reading was the result of the sample taken at the home where the door was blown into the house subsequent to the blast. Black powder was the reading; therefore, we knew that we were dealing with a low explosive. Some bomb makers are comfortable with certain explosive materials and IED devices. This knowledge of bomb makers’ preferences gives investigators some insight into what person or group constructed and deployed the device. Bomb makers stick to what is comfortable and accessible. Another investigative tip is to ask witnesses, victims, and other first responders about the color and smell of the smoke. If the color of the smoke is white, a large amount of chlorates was used. Some bomb makers will use a specific explosive material with a high level of chlorates because that is how they were taught. The smell is another good tip. For example, if a witness informs an investigator that he smelled a “sweet” smell, we can surmise that an icing sugar or confectioner’s sugar was used as a fuel when the explosive material was mixed. Certain terrorist groups and criminal gangs will use icing sugar because of its availability and simplicity in constructing an IED. This may tell us who made the IED. [Photo courtesy of the Akron (OH) Fire Department Investigations Unit.]

Quinary blast injuries. In some parts of the world, chemical, biological, and radiological additions to explosive devices are not uncommon. These substances are obviously placed into a device to increase the lethality. Radiological materials are more difficult to procure; however, chemical substances may have a likelier possibility of being added to a device. Biological substances added to a bomb such as ricin or anthrax will more than likely be consumed because of the thermal effects of the blast. However, it is not out of the question that a suicide bomber may be carrying a communicable disease such as HIV, AIDS, Hepatitis C, and so on. Exposures to bodily fluids from those injured may also pose a risk to contracting a deadly disease. Bone fragmentation is another point of concern if a person close to the suicide bomber or other victims sustain penetrating trauma because of flying bone pieces. Hasty decontamination with water is a necessity. Be ready to request a hazardous materials team, a decontamination apparatus, and federal agencies if a dirty bomb or bodily fluids are present. Federal law enforcement organizations and emergency management groups will also respond if chemical, biological, or radiological materials are present and released into the environment.

Fighting fires, effecting rescues from burning structures, extricating victims from motor vehicle collisions, and providing quality emergency medical services are our “bread and butter.”

We, as first responders, will perform our jobs to the best of our abilities at all times. If someone would have asked me 20 years ago if I were ready to recognize and mitigate situations that included homemade explosive precursors and fully constructed IEDs, I would have retorted that first responder duties like that are not in my job description. Times have changed drastically in my 19 years on the job. Criminals have become more astute and sophisticated when committing crimes. The police and other state and federal law enforcement organizations are not the only government agencies that will need to spearhead the united effort to control and mitigate the dangers of explosives. We must work together with our partners in blue to keep our communities and each other safe. If you are not trained in explosives, visit the Energetic Materials section of the New Mexico Tech’s Web site (www.emrtc.nmt.edu). It offers various courses at the awareness level. Situational awareness and scene safety will become second nature if you have the educational foundation and continued training.

Akron Fire Departmental: Standard Operating Guidelines (2022): Section 1500.00 Administration Subdivision; subsections 1555.01-1555.08. (Section 1555.01 revision September 2008).

Department of Homeland Security (DHS): Federal Emergency Management Administration (2000-2010) Incident Response to Terrorist Bombings; PER 230-1. Energetic Materials Research and Testing Center (EMRTC): New Mexico Institute of Mining and Technology, New Mexico Tech. version 3.1.1.

Department of Homeland Security (DHS): Federal Emergency Management Administration (2015) Homemade Explosives: Awareness, Recognition, and Response. Energetic Materials Research and Testing Center (EMRTC): New Mexico Institute of Mining and Technology, New Mexico Tech. version 1.0.

DHS/FEMA (2014) Medical Preparedness and Response for Bombing Incidents: MGT-348/PER-233; TEEX, NERRTC, NMT.

Eastman, A., Flory, D. (2019) TECC: Tactical Emergency Casualty Care, 2nd Edition. Course Manual; National Association of Emergency Medical Technicians (NAEMT), Jones & Bartlett Learning, publisher.

Gerecht, R. (2014) “Trauma’s Lethal Triad of Hypothermia, Acidosis & Coagulopathy Create a Deadly Cycle for Trauma Patients.” Journal of Emergency Medical Services (JEMS) April 2014.

NFPA 921 (2014) National Fire Protection Association: Guide for Fire & Explosion Investigations; NFPA Publications Quincy, MA: 8th Edition.

Springer, B. & Verbillion, M. (2017) March/April: Trauma Reports: Practical, Evidence-Based Reviews in Trauma Care; Volume 18, NO. 2.

United States Bomb Data Center (USBDC). 2016 Explosives Incident Report. Accessed on May 14, 2018, at https://www.atf.gov/explosives/docs/report/2016-explosives-incident-report/download.

USDOJ (FBI/ATF) (2008) Indicators and warnings for Homemade Explosives Handbook.

JARRED R. ALDEN, M.A., FFII, NRP, is a firefighter/paramedic operations officer for the Akron (OH) Fire Department (AFD). He has worked 19-plus years as a firefighter and 17-plus years as a paramedic and is a member of the Akron Police Department SWAT Tactical Medic program. Alden was previously a member of the rescue/recovery dive team. He has NAUI Dive and Public Safety Dive certifications in open water and dry suit and has worked as an arson investigator and the assistant bureau manager for the AFD fire investigation unit’s bureau. His fire investigations certifications are basic origin and cause and advanced origin and cause. Alden is also a nationally registered paramedic and an Ohio state-certified paramedic. He is ITLS, ACLS, PALS, PITLS, and BLS certified. He is a certified firefighter II through the state of Ohio. Alden has a master of arts degree in applied behavioral sciences from Wright State University and a baccalaureate degree in sociology/criminology from Urbana University. He served as a collegiate professor of sociology at the University of Akron for six years and has presented at FDIC International, JEMS, the Ohio State University Fire/EMS conference, and the Ohio Tactical Officers Association conference.