By Martin Greene

The time is now for hazmat teams to develop and/or expand their working relationship with their local bomb squad. Why?

• October 2010: Three hazmat team members in North Carolina were injured while assisting bomb squad members at a location suspected of manufacturing triacetone triperoxide (TATP).

• November 2010: California authorities discovered more than 9 pounds of explosives in and around a home, including hexamethylene triperoxide diamine (HMTD), pentaerythritol tetranitrate (PETN) and erythritol tetranitrate (ETN).

Hazmat teams need to understand and be ready to face the threat of home-made explosives (HMEs) and the hazards involved in scene assessment when responding to incidents at illicit labs or with unknown chemicals.

Assessing the hazards of an HME lab or its precursors begins with a basic knowledge of the components of these types of incidents. Two common components contained in illicit explosives are organic peroxides and nitro-containing compounds.

Identifying Organic Peroxides
Organic peroxides are organic compounds containing the peroxide functional group (R-OO-R). In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction(s) regardless of the size of the molecule it is a part of.

The O-O bond in this particular functional group breaks easily and forms free radicals of the form R-O. Thus, organic peroxides are useful for initiating some types of polymerization, or the bonding of two or more monomers, such as the epoxy resins used in glass-reinforced plastics. Methyl ethyl ketone peroxide (MEKP) and benzyl peroxide are commonly used for this purpose. However, this same property also means that organic peroxides can either intentionally or unintentionally initiate explosive polymerization in materials with unsaturated chemical bonds.This process has been used to make explosives.
http://en.wikipedia.org/wiki/Organic_peroxide

Organic peroxides are available as solids (usually fine powders), liquids or pastes. Organic peroxides, like their inorganic counterparts, are powerful bleaching agents. Some materials, such as water, odorless mineral spirits and some phthalate esters, do not react with organic peroxides and are often used to dilute them. The main hazard related to organic peroxides is their explosive potential. Organic peroxides may also be toxic or corrosive. Depending on the material, route of exposure (inhalation, eye or skin contact, or swallowing) and dose or amount of exposure, they could harm the body.

It is the double oxygen (R-OO-R) of the peroxy group that makes organic peroxides both useful and hazardous. Chemically unstable, the group can easily decompose, giving off heat at a rate that increases as the temperature rises. Many organic peroxides give off flammable vapors when they decompose. These vapors can easily catch fire or explode.

Organic peroxides can also be strong oxidizing agents. Combustible materials contaminated with most organic peroxides can catch fire easily and burn intensely (i.e., deflagrate). This means that the burn rate is very fast: it can vary from 1 meter per second to hundreds of meters per second. Also, the combustion rate increases as the pressure increases, and the combustion (or reaction) zone can travel through air or a gaseous medium faster than the speed of sound. However, the speed of combustion in a solid medium does not exceed the speed of sound.

Triacetone Triperoxide (TATP)
TATP is an organic peroxide that acts as a high explosive. It is highly susceptible to heat, friction and shock. Because of its instability, it has been called the “Mother of Satan”. The explosion of TATP does not generate much energy. In conventional high explosives such as TNT, each molecule contains both a fuel component and an oxidizing component. When the explosive detonates, the fuel part is oxidized, and as this combustion reaction spreads, it releases large amounts of heat. The explosion of TATP involves entropy burst, which is the result of the formation of one ozone and three acetone molecules from every molecule of TATP in the solid state. Just a few hundred grams of the material produce hundreds of liters of gas in a fraction of a second.

TATP can be prepared easily in a basement lab using commercially available starting materials obtained from hardware stores, pharmacies and stores selling cosmetics. TATP is a fairly easy explosive to make, as far as explosives manufacturing goes. All it takes is acetone, hydrogen peroxide (3% medicinal peroxide is not concentrated enough) and a strong acid like hydrochloric or sulfuric acid.

TATP was used as the explosive in the July 2005 London bombings, a series of coordinated terrorist bomb blasts that hit London’s public transport system. Richard Reid, who attempted to down American Airlines Flight 63 with a bomb concealed in his shoe, employed a device containing plastic explosives with a TATP trigger.

http://www.3dchem.com/ moremolecules.asp?ID=312&othername=TATP
http://www.globalsecurity.org/military/systems/munitions/tatp.htm

Methyl Ethyl Ketone Peroxide (MEKP)
MEKP is an organic peroxide, a high explosive similar to TATP, and is very dangerous to prepare. MEKP is a colorless, oily liquid at room temperature and pressure, while TATP is a white solid. It’s slightly less sensitive to shock and temperature than TATP and more stable in storage. It’s prepared from methyl ethyl ketone (MEK) and hydrogen peroxide.

Diluted solutions of MEKP are used in industry and by hobbyists as the catalyst that initiates the polymerization of polyester resins used in glass-reinforced plastic and casting. MEKP does this through the production of free radicals.

It has been reported that MEKP might be the explosive that was to be used in the alleged 2006 transatlantic aircraft plot to destroy planes flying from the United Kingdom to the United States. TATP is another reported possibility.
http://www.3dchem.com/molecules.asp?ID=313

Hexamethylene Triperoxide Diamine (HMTD)
HMTD is a high-explosive organic chemical compound, first synthesized in 1885. The theorized structure lends itself well to acting as an initiating, or primary, explosive. While still quite sensitive to shock and friction, it was relatively stable compared to other initiating explosives of the time, such as mercury fulminate, and proved to be relatively inexpensive and easy to synthesize.

Despite no longer being used in any official application, it remains a fairly popular HME and has been used in a large number of suicide bombings throughout the world. It was possibly used in the July 2005 London bombings. It’s also claimed that it was to be used in the planned explosive in the 2006 transatlantic aircraft plot.

Like other organic peroxides such as TATP, HMTD is an unstable compound that is sensitive to shock, friction and heat. This makes the substance extremely dangerous to manufacture. It also reacts with most common metals, which can lead to detonation. HMTD is very stable when pure (acid-free) and does not quickly sublimate like its acetone counterparts.
http://www.3dchem.com/molecules.asp?ID=427

Nitro-Containing Compounds
Nitro compounds are organic compounds that contain one or more nitro functional groups (NO2). They are often highly explosive, especially when the compound contains more than one nitro group and is impure.

Pentaerythritol tetranitrate (PETN)
PETN is a major ingredient of Semtex and belongs to the same chemical family as nitroglycerin. It’s one of the most powerful explosives made today and is a favorite among terrorists because its colorless crystals are hard to detect in a sealed container.

PETN is relatively stable and is detonated either by heat or a shock wave. A little more than 100 grams of the substance could destroy a car, experts say. Richard Reid, the “shoe bomber,” tried to set off a PETN device on an American Airlines jet bound for Miami in 2001.

In December 2009, PETN was found to be in the possession of Nigerian Umar Farouk Abdulmutallab, the “underwear bomber.” He had attempted to blow up Northwest Airlines flight 253 as it approached the Detroit airport from Amsterdam. Abdulmutallab was in a window seat and had the device strapped to his leg, against the body of the aircraft. Abdulmutallab’s bomb involved a syringe and a soft plastic container filled with 80 grams of PETN.

Experts believe the syringe may have been converted into an electric detonator or, more likely, was filled with a liquid detonator that would have made the device extremely hard to detect through the usual airport security measures.

http://www.irishtimes.com/newspaper/world/2010/1101/1224282401319.html

Erythritol tetranitrate (ETN)
ETN is an explosive compound chemically similar to PETN. However, it’s thought to be one-third more sensitive to friction and impact. ETN is not well known, but in recent years it has been used by amateur experimenters to replace PETN in improvised detonation cords or in boosters to initiate larger, less sensitive explosive charges. Due to the availability of erythritol as a natural sweetener and its relative ease of production in relation to PETN, ETN is a favored HME compound for the amateur experimenter.

Ingesting ETN or prolonged skin contact can lead to absorption and what is known as a “nitro headache.”

http://en.wikipedia.org/wiki/Erythritol_tetranitrate

Detecting Peroxide & Nitro-Based Compounds
The hazards of detecting peroxide and nitro-based compounds usually outweigh any attempt for a hazmat team to analyze suspected material without direction and direct assistance from a bomb squad. Raman technology is usually the first choice for materials in question, although it’s not without its own hazards. Handheld models are easily adapted for robotic use, with a flex probe and timer options for a hands-off, timed test that eliminates on-target monitoring during analysis. While most training in the use of Raman technology makes mention of the hazards of testing dark materials (bottles, powders, etc.) because of the build-up of heat, hazards testing “white” powders can occur because of the impurities in the suspected material or the background of the material itself (see Thermo Fisher Technical Service Bulletin TSB 0001).

Other testing, such as wet chemistry, may cause a detonation caused by the build-up of heat during the chemical reaction of the test. A peroxide test strip can detect 0.5 to 25 ppm of peroxide, but this can also cause a detonation due to the shock-sensitive properties of the material.

Any test, such as Fourier transform-infrared (FT-IR) spectroscopy, narcotic field test kits or any type of detection that would require handling or manipulation of the suspected materials can cause a significant reaction, leading to detonation.

The best solution for any hazmat team is to maintain excellent situational awareness and incorporate a bomb squad response to these incidents.
Precursors to watch for:
• Hydrogen peroxide
• Wood bleach
• Ethanol
• Sulfuric acid
• Hexamine (solid fuel for camp stoves)
• Hair coloring
• Acetone
• Nitro methane
• Citric acid

Indicators of manufacturing:
• Foul odors/caustic fumes
• Metal corrosion
• Strong chemical odors from exterior drains or sewers
• Dead vegetation
• Paint discoloration
• Structural damage
• Multiple fans in multiple windows
• Refrigerators and coolers

http://www.bluesheepdog.com/2007/10/26/peroxide-based-explosives-co...

Conclusion
A successful relationship between the local hazmat team and bomb squad is critical in providing a safer approach to these types of incidents. Both groups will benefit from the sharing of resources and knowledge of the chemical and energetic hazards that these precursors pose to the emergency response community and the public they are sworn to protect.

Martin Greene is the fire chief of the Bourne Fire & Rescue Department in Bourne, Mass. He is a member of the Department of Fire Services, District One Hazmat Team and a paramedic. He is a member of the IAFC’s Hazmat Committee and the past deputy director of the Department of Fire Services Hazardous Materials Response Division in Massachusetts. He was a primary developer of the Massachusetts Joint Hazard Assessment Team (JHAT), which is comprised of select members of the state’s hazmat teams and the Massachusetts State Police Bomb Squad. JHAT was developed to respond to chemicals and energetic materials incidents that may cause harm to responders and to render safe those incidents.


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