11. Explosions Flashcards
what does this mean
explosives
describe the winnipeg bomb incident
- in 2024
- winnipeg police called the bomb unit after a suspicious item was found
what did the “bomb” look like in the winnipeg bomb incident
- having a blinking red light
- with visible wires
- some smoke coming from it
in the winnipeg bomb incident, how long did it take for the bomb to be disengaged
- 2 hours
- discovered at 10:30pm, and disengaged at 12:30am
how did they disengage the bomb in the winnipeg bomb incident
a bomb robot did it
what is an explosive
- any chem compound or mech mixture
- that when subjected to heat, impact, friction, detonation, or other suitable initiation
- undergoes rapid chem change
- evolving large volumes of highly heated gases
- that exert pressure on the surrounding medium
true/false an explosive only applies to materials that detonate
- false
- those that detonate or deflagrate
what does it take for an explosion to occur
- fuel
- oxidation (generally air)
- an ignition source (spark, cigarette, static electricity)
what does IEDs stand for
improvised explosive devices
true/false IEDs are a critical priority to law enforcement and national security
true
what are used as explosive fillers for IEDs
- commercially-available firearm propellants
- consumer fireworks
what does HMEs stand for
homemade explosives
why are HMEs an increasing threat
due to the ease of fabrication using reagents sourced from common household chemicals
what were the objectives of Explosion and Bombing Scene Investigation
- describe the historical development of explosives
- high and low explosives (primary/secondary)
- legal uses of explosives
- illegal uses of explosives
what are some legal uses of explosives
- blasting
- propellants
- military
- pyrotechnic
what does a guide for explosion and bombing scene investigations say about the chemistry of primary high explosives
- diff types and formulations of primary high explosives
- website or other documentation that describes manufacturing procedures for primary high explosives
what does a guide for explosion and bombing scene investigations say about the chemistry of secondary high explosives
- diff types and formulations of secondary high explosives
- methods of manufacture/preparation of secondary high explosives
- use direct physical exam, and use a stereoscope to examine them
what is an example of a primary high explosive
TATP
what is an example of a secondary high explosive
- dynamite
- TNT
- ANFO
what does TATP stand for
triacetone triperoxide
describe the structure of TATP
- organic peroxide
- 3 peroxide groups
- cyclical structure
- no nitro group
what does TNT stand for
trinitrotoluene
what is one of the most commonly used explosives for military, industrial, and mining applications
TNT
why is TNT valued
- its insensitivity to shock and friction
- reduced risk of accidental detonation compared to more sensitive explosives
what is an example of a sensitive explosive
nitroglycerin
describe the structure of TNT
- 3 nitro groups
- benzene group
where is ANFO used
- bulk industrial explosive
- coal mining
- quarrying
- metal mining
- civil construction
what is the role of ammonium nitrate in ANFO
acts as the oxidizing agent and absorbent for fuel
what does ANFO stand for
ammonium nitrate fuel oil
describe the composition of ammonium nitrate
- a salt
- made up of pos-charged ammonium ion and
- neg-charged nitrate ion
what is the composition of ANFO
- ammonium nitrate
- 6% number 2 fuel oil
what are some number 2 fuel oils
- diesel
- kerosene
what is ANFO commonly used for
mining and blastic
what is the common form of ANFO
solid
when was ANFO used
Oklahoma City bombing
what is the common form of TATP
crystalline solid
when was TATP used as an IED
2005 bombings in London
what is the common use of Semtex, C-4
primarily military
what is the common form of Semtex, C-4
plastic solid
when was Semtex, C-4 used as an IED
irish republican army bombings
what is the common use of EGDN
component of low-freezing dynamite
what is the common form of EGDN
liquid
when was EGDN used as an IED
millenium bomber, intended for LAX 1999
what is the common use of urea nitrate
fertilizer
what is the common form of urea nitrate
crystalline solid
when was urea nitrate used as an IED
world trade center 1993
what is the common use of smokeless power
ammo
what is the common form of smokeless powder
solid
when was smokeless powder used as an IED
olympic park bombings
Identification of explosives is of special interest in forensic _____
chemistry
Identifying unused explosives (pre-blast analysis) is a key point in what
- counterterrorism
- public security
what does CERL stand for and what is it
- canadian explosives research lab
- the only canadian government lab, and one of few in the world
- that offers explosives testing, analysis, certification and research related to explosives + their components
how was the pan-European Forensic Substance Database on Explosives established
- Identification and differentiation of commercial and military explosives
- via mass spec + other methods
in pan-European Forensic Substance Database on Explosives, how many explosive samples were differentiated
36/41
describe the Oklahoma city bombing
- april 19 1995
- a truck bomb exploded in front of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma
what was the bomb made of in the Oklahoma City bombing
- improvised from
- ammonium nitrate fertilizer
- diesel fuel
- nitromethane
how many people died in the Oklahoma City bombing
169
In the Oklahoma City bombing, the investigators Conducted more than ______ interviews
28,000
In the Oklahoma City bombing, the investigators Followed more than _____ investigative leads
43,000
In the Oklahoma City bombing, the investigators Collected more than ____ tons of evidence
3
In the Oklahoma City bombing, the investigators Searched more than _______ hotel registration records
13.2 million
In the Oklahoma City bombing, the investigators Reviewed more than ______ truck rental records
3.1 million
In the Oklahoma City bombing, the investigators Searched more than ______ airline reservation records.
682,000
describe the london bombings
a series of coordinated attacks on the london transportation system on the morning of July 7th 2005
how many people were killed/ injured in the london bombing
- 52 people killed
- hundreds more injured
what was the explosive used in the london bombings
- five IED
- TATP was identified, as it was found in the london apartment of the biochemist
what trace evidence was found after detonation of IEDs
- battery,
- lid of metal can,
- mobile phone,
- printed circuit board,
- metal can,
- handle and
- combination lock of suitcase,
- push button
how should you collect and preserve explosion evidence
- airtight containers to collect solid items
- keep containers separate
- collect “substrate control”
true/false plastic bags should be used to collect and preserve explosion evidence
false
ASTM international’s FS committee has which 3 standards
- terminology
- intact explosives
- explosive residue
what are the issues with post-blast analysis
- can be hard to find a representative sample since the amount available may be very small
- composition changes from one case to another
- different matrices can be quite complex
- explosions are a non-controlled and heterogenous phenomenon
- identification of chem content and interpretation problems because they are composed of ordinary chems, which are released by materials of daily use
- other evidence (DNA/fingerprints) may be comprimised
what questions should we ask when tracking the explosive source
- are chem signatures for sourcing explosive materials to their manufacturing source preserved after detonation?
- which signature types are best preserved?
in the tracking the explosive source-post blast study, how many TNT samples were recovered?
~30 out of 108
in the tracking the explosive source-post blast study, how many RDX samples were recovered?
0
describe the Identification of post-blast explosive residues using direct-analysis-in-real-time and mass spectrometry (DART-MS) paper
- a variety of simulated IEDs were made o replicate post-blast debris
- they collected swabs, and ran a mass spec
- depending on the ions found, diff compositions could be determined
- peaks in the mass spec is directly related to the mass of the compound
explain how the Identification of post-blast explosive residues using direct-analysis-in-real-time and mass spectrometry (DART-MS) worked
- peaks in mass spec is the mass of compound
- the molecular formula leads to molecular weight, which leads to mass, which is m/z
in the Identification of post-blast explosive residues using direct-analysis-in-real-time and mass spectrometry (DART-MS) paper, what did the sampling thing tell us
- swab is a better method for sampling than direct method
- more peaks= more ions in Mass spec= better method of sampling
in the Identification of post-blast explosive residues using direct-analysis-in-real-time and mass spectrometry (DART-MS) paper, how much TATP was found after 3 months
40g
in the Identification of post-blast explosive residues using direct-analysis-in-real-time and mass spectrometry (DART-MS) paper, how much TATP was found after 5 months
5g
in the study of survival of fingerprints after detonation of IEDs, how many deposited FPs were detected
- 52/115
- ~50%
- score 0-3
how did they do the survival of DNA from post-blast pipe bomb fragments study
- cell suspension used to deposit cell and thus DNA on the device
- # of cells is related to # of DNA which is related to mass of DNA
what were the findings of the survival of DNA from post-blast pipe bomb fragments study
- only ~15% of expected DNA recovered
- heterogenous distribution of DNA amount
in the survival of DNA from post-blast pipe bomb fragments study, how long did they test for
- 1 week after detonation
- then 3 months
true/false DNA amount decreases after 3 months
true
in the survival of DNA from post-blast pipe bomb fragments study, what did we learn after comparing the 1 week to 3 month collection
- on average, loss of DNA from 1 week to 3 months is high
- 98%
