View source for C-4 (explosive)

{{short description|Variety of plastic explosive}}
{{Infobox weapon
| name               = C-4
| image              = Exploding pumpkins 131106-F-YU668-233.jpg
| image_size         = 300
| caption            = Blocks of C-4 cut to size during a demo training session, showing the white plastic explosive material
| origin             = United States
| type               = High-yield chemical explosive
| is_explosive       = yes
| is_UK              = <!-- Service history -->
| service            = 
| used_by            = [[United States]]
| wars               = [[Vietnam War]] <br /> [[War on Terror]] <br />
[[2022 Russian invasion of Ukraine]]
<!-- Production history -->| designer           = 
| design_date        = 1956
| manufacturer       = 
| unit_cost          = 
| production_date    = 1956–current
| number             = 
| variants           = PE-4, M112
<!-- General specifications -->| spec_label         = M112
| weight             = {{convert|1.25|lb|kg|abbr=on}}<ref name="global" />
| length             = {{convert|11|in|cm|abbr=on}}<ref name="global" />
| part_length        = 
| width              = {{convert|2|in|cm|abbr=on}}<ref name="global" />
| height             = {{convert|1.5|in|cm|abbr=on}}<ref name="global" />
| diameter           = 
| crew               = 
| passengers         = <!-- Explosive specifications -->
| filling            = [[RDX]]
| filling_weight     = 91%
| detonation         = [[Pentaerythritol tetranitrate|PETN]]-based [[detonating cord]]
| velocity           = 4400&nbsp;m/s @ 0.9&nbsp;g/cm<sup>3</sup>, 6600 m/s @ 1.5&nbsp;g/cm<sup>3</sup>, 6900&nbsp;m/s @ 1.6&nbsp;g/cm<sup>3</sup><ref>{{Cite book |title=Composition C-4 |publisher=Paul Lezica }}</ref>
| yield              = High
}}

'''C-4''' or '''Composition C-4''' is a common variety of the [[plastic explosive]] family known as [[Composition C]], which uses [[RDX]] as its [[explosive]] agent. C-4 is composed of explosives, plastic binder, [[plasticizer]] to make it malleable, and usually a marker or odorizing [[taggant]] chemical. C-4 has a texture similar to [[modelling clay]] and can be molded into any desired shape. C-4 is relatively insensitive and can be detonated only by the [[shock wave]] from a [[detonator]] or blasting cap.

A similar British plastic explosive, also based on [[RDX]] but with a plasticizer different from that used in Composition C-4, is known as '''PE-4''' (Plastic Explosive No. 4).

== Development ==
C-4 is a member of the Composition C family of chemical explosives. Variants have different proportions and plasticisers and include compositions C-2, C-3, and C-4.<ref>{{cite book|author1=Rudolf Meyer|url=http://www.wiley.com/WileyCDA/WileyTitle/productCd-3527316566.html|title=Explosives|author2=Josef Köhler|author3=Axel Homburg|date=September 2007|publisher=Wiley-VCH|isbn=978-3-527-31656-4|page=63}}</ref> The original RDX-based material was developed by the British during [[World War II]] and redeveloped as Composition C when introduced to the U.S. military. It was replaced by Composition C-2 around 1943 and later redeveloped around 1944 as Composition C-3. The toxicity of C-3 was reduced, the concentration of RDX was increased, giving it improved safety during usage and storage. Research on a replacement for C-3 was begun prior to 1950, but the new material, C-4, did not begin pilot production until 1956.<ref name="TM-9-1300-2142">{{Citation |last=Headquarters, U.S. Department of the Army |title=Military Explosives TM 9-1300-214 |date=25 Sep 1990 |url=http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf |pages=A-13 (323) |postscript=. |archive-url=https://web.archive.org/web/20220819084946/http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf |archive-date=19 August 2022}}</ref>{{rp|125}} C-4 was submitted for patent as "Solid Propellant and a Process for its Preparation" March 31, 1958, by the [[Phillips Petroleum Company]].<ref>{{cite web|author1=D, G.E.|title=US Patent 3,018,203|url=https://patents.google.com/patent/US3018203|access-date=15 July 2014|publisher=Google Patents}}</ref>

== Characteristics and uses ==

=== Composition ===
The Composition C-4 used by the [[United States Armed Forces]] contains 91% [[RDX]] ("Research Department Explosive", an explosive [[nitroamine]]), bound by a mixture of 5.3% [[dioctyl sebacate]] (DOS) or [[dioctyl adipate]] (DOA) as the plasticizer (to increase the [[plasticity (physics)|plasticity]] of the explosive), thickened with 2.1% [[Polyisobutene|polyisobutylene]] (PIB, a [[synthetic rubber]]) as the [[binder (material)|binder]], and 1.6% of a [[mineral oil]] often called "process oil". Instead of "process oil", low-viscosity [[motor oil]] is used in the manufacture of C-4 for civilian use.<ref name="atf">{{cite journal|last1=Reardon|first1=Michelle R.|last2=Bender|first2=Edward C.|year=2005|title=Differentiation of Composition C4 Based on the Analysis of the Process Oil|journal=Journal of Forensic Sciences|volume=50|issue=3|pages=1–7|doi=10.1520/JFS2004307|url=http://www.astm.org/DIGITAL_LIBRARY/JOURNALS/FORENSIC/PAGES/JFS2004307.htm|publisher=Bureau of Alcohol, Tobacco, Firearms, and Explosives, Forensic Science Laboratory|location=Ammendale, MD|issn=0022-1198}}</ref>

The British PE4 consists of 88.0% RDX, 1.0% pentaerythrite dioleate and 11.0% DG-29 [[Lithium soap|lithium grease]] (corresp. to 2.2% [[lithium stearate]] and 8.8% mineral oil [[British Pharmacopoeia|BP]]) as the binder; a taggant (2,3-dimethyl-2,3-dinitrobutane, [[DMDNB]]) is added at a minimum of 0.10% weight of the plastic explosive, typically at 1.0% mass.  The newer PE7 consists of 88.0% RDX, 1.0% DMDNB taggant and 11.0% of a binder composed of low molecular mass [[hydroxyl-terminated polybutadiene]], along with an [[antioxidant]] and an agent preventing hardening of the binder upon prolonged storage. The PE8 consists of 86.5% RDX, 1.0% DMDNB taggant and 12.5% of a binder composed of di(2-ethylhexyl) sebacate thickened with high molecular mass polyisobutylene.

Technical data according to the [[United States Department of the Army|Department of the Army]] for the Composition C-4 follows.<ref name ="armymanual 8-111" />
{| class="wikitable"
 |-
 | Theoretical '''maximum density''' of the mixture, grams per cubic centimeter
 | style="text-align:right;" | 1.75
 |-
 | '''Nominal density''', grams per cubic centimeter
 | style="text-align:right;" | 1.72658
 |-
 | '''Heat of formation''', calories per gram
 | style="text-align:right;" | −32.9 to −33.33
 |-
 | Max heat of detonation with liquid water, kilocalories per gram
 | style="text-align:right;" | 1.59 (6.7 MJ/kg)
 |-
 | Max heat of detonation with gaseous water, kilocalories per gram
 | style="text-align:right;" | 1.40 (5.9 MJ/kg)
 |-
 | Remains plastic with no exudation, Celsius
 | style="text-align:right;" | −57 to +77
 |-
 | '''Detonation pressure''' with density of 1.58 grams per cubic centimeter, kilobars
 | style="text-align:right;" | 257
 |}

==== Manufacture ====
C-4 is manufactured by combining the above ingredients with binders dissolved in a [[solvent]]. Once the ingredients have been mixed, the solvent is extracted through drying and filtering. The final material is a solid with a dirty white to light brown color, a putty-like texture similar to modeling clay, and a distinct smell of motor oil.<ref name ="armymanual 8-111" /><ref name="fuelsource" /><ref name="homelandpresentation">{{cite web | url=https://info.publicintelligence.net/DHS-Explosives.pdf | title=Introduction to Explosives | publisher=U.S. Department of Homeland Security | work=C4: Characteristics, Properties, and Overview | access-date=18 July 2014 | pages=4–5}}</ref> Depending on its intended usage and on the manufacturer, there are differences in the composition of C-4.  For example, a 1990 U.S. Army technical manual stipulated that Class IV composition C-4 consists of 89.9±1% RDX, 10±1% polyisobutylene, and 0.2±0.02% dye that is itself made up of 90% [[Lead(II) chromate|lead chromate]] and 10% [[Carbon black|lamp black]].<ref name="armymanual 8-111">{{citation | url=http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf | title=Department of the Army Technical Manual – Military Explosives| author=Headquarters, U.S. Department of the Army | date=25 Sep 1990 |postscript=.}}</ref> RDX classes A, B, E, and H are all suitable for use in C-4. Classes are measured by granulation.<ref>{{citation | url=http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf | title=Department of the Army Technical Manual – Military Explosives| author=Headquarters, U.S. Department of the Army | date=25 Sep 1990 | pages=8–37–38 (124–125)|postscript=.}}</ref>

The manufacturing process for Composition C-4 specifies that wet RDX and plastic binder are added in a stainless steel mixing kettle. This is called the aqueous slurry-coating process.<ref name="bae">{{cite web |title=Recent Developments in Composition C-4: Towards an Alternate Binder and Reduced Sensitivity|last1=Owens|first1=Jim |last2=Vinh |first2=Paul |url=http://www.dtic.mil/ndia/2009insensitive/10Aowens.pdf|archive-url=https://web.archive.org/web/20130719235154/http://www.dtic.mil/ndia/2009insensitive/10Aowens.pdf|url-status=dead|archive-date=July 19, 2013|publisher=[[BAE Systems]] OSI|location=Holston Army Ammunition Plant}}</ref> The kettle is tumbled to obtain a homogeneous mixture. This mixture is wet and must be dried after transfer to drying trays. Drying with forced air for 16 hours at 50&nbsp;°C to 60&nbsp;°C is recommended to eliminate excess moisture.<ref name="armymanual 8-111" />{{rp|198}}

C-4 produced for use by the U.S. military, commercial C-4 (also produced in the United States), and PE-4 from the United Kingdom each have their own unique properties and are not identical. The analytical techniques of time-of-flight [[secondary ion mass spectrometry]] and [[X-ray photoelectron spectroscopy]] have been demonstrated to discriminate finite differences in different C-4 sources. Chemical, morphological structural differences, and variation in atomic concentrations are detectable and definable.<ref>{{cite journal|last1=Mahoney|first1=Christine M.|last2=Fahey|first2=Albert J.|last3=Steffens|first3=Kristen L.|last4=Benner|first4=Bruce A.|last5=Lareau|first5=Richard T.|year=2010|title=Characterization of Composition C4 Explosives using Time-of-Flight Secondary Ion Mass Spectrometry and X-ray Photoelectron Spectroscopy|journal=[[Analytical Chemistry (journal)|Analytical Chemistry]] |volume=82|issue=17|pages=7237–7248|doi=10.1021/ac101116r|pmid=20698494}}</ref>

=== Detonation ===
[[File:C4 explosion.jpg|thumb|A detonation within a blast-resistant trash receptacle using a large C-4 explosive charge]]

C-4 is very [[Explosive material#Stability|stable]] and [[Insensitive munition|insensitive]] to most physical shocks. C-4 cannot be [[Detonation|detonated]] by a gunshot or by dropping it onto a hard surface. It does not explode when set on fire or exposed to [[microwave]]s.<ref name="microwave">{{cite web|last1=Nagy|first1=Brian|title=Grosse Point Blank Microwave C4 Mercury Switch|url=https://www.cs.cmu.edu/~bnagy/GPB-MercurySwitch/|website=Carnegie Mellon University|access-date=14 July 2014}}</ref> Detonation can be initiated only by a [[Shock wave|shockwave]], such as when a detonator inserted into it is fired.<ref name="fuelsource" />
When detonated, C-4 rapidly [[Chemical decomposition|decomposes]] to release nitrogen, water and [[Oxocarbon|carbon oxides]] as well as other gases.<ref name="fuelsource" /> The detonation proceeds at an [[Detonation velocity|explosive velocity]] of {{convert|8092|m/s|ft/s|abbr=on}}.<ref name="Ribbands">{{cite web|url=http://www.ribbands.co.uk/prod-c4.php|work=Ribbands Explosives|title=C4 product page|access-date=2014-05-21|archive-url=https://web.archive.org/web/20170517101148/http://www.ribbands.co.uk/prod-c4.php|archive-date=2017-05-17|url-status=dead}}</ref>

A major advantage of C-4 is that it can easily be molded into any desired shape to change the direction of the resulting explosion.<ref name="fuelsource" /><ref name="shape">{{cite web|last1=Nordin|first1=John|title=Explosives and Terrorists|url=http://www.aristatek.com/Newsletter/05%2007%20July/The%20First%20Responder%20Explosives%20and%20Terrorists.htm|website=The First Responder|publisher=AristaTek|access-date=14 July 2014}}</ref> C-4 has high cutting ability. For example, the complete severing of a {{convert|36|cm|in|adj=on}} deep [[I-beam]] takes between {{cvt|680|and|910|g|lb}} of C-4 when properly applied in thin sheets.<ref>{{cite web |url=https://apps.dtic.mil/dtic/tr/fulltext/u2/479244.pdf |title=Steel cutting with high-explosive charges |id=Report 1839 |first=James A. |last=Dennis |date=December 1965 |publisher=U. S. Army Engineer Research And Development Laboratories |place=Fort Belvoir, Virginia |website=apps.dtic.mil|archive-url=https://web.archive.org/web/20190502002330/https://apps.dtic.mil/dtic/tr/fulltext/u2/479244.pdf |archive-date=2019-05-02 }}</ref>

=== Form ===
Military grade C-4 is commonly packaged as the M112 [[demolition]] block. The demolition charge M112 is a rectangular block of Composition C-4 about {{convert|2|x|1.5|in}} and {{convert|11|in}} long, weighing {{convert|1.25|lb|g|abbr=on}}.<ref name="global">{{Cite web |title=Explosives – Compositions |url=https://www.globalsecurity.org/military/systems/munitions/explosives-compositions.htm |archive-url=https://web.archive.org/web/20220819084947/https://www.globalsecurity.org/military/systems/munitions/explosives-compositions.htm |archive-date=19 August 2022 |access-date=14 July 2014 |publisher=[[GlobalSecurity.org]]}}</ref><ref name=M15>{{Cite book
 | publisher = Headquarters, Department of the Army
 | title = Use of Mine, Antitank: HE, Heavy, M15 as a Substitute for Charge Assembly Demolition, M37 Or M183
 | date = 1971
}}</ref> The M112 is wrapped in a sometimes olive color [[BoPET|Mylar]]-film container with a [[Pressure-sensitive tape|pressure-sensitive adhesive tape]] on one surface.<ref>{{cite web |title=M112 |url=http://www.aollc.biz/pdf/DemoBlockM112.pdf |publisher=American Ordnance |access-date=19 July 2014 |archive-url=https://web.archive.org/web/20150322080434/http://www.aollc.biz/pdf/DemoBlockM112.pdf |archive-date=22 March 2015 |url-status=dead }}</ref><ref>{{cite book |title=ATF Law Enforcement Guide to Explosives Incident Reporting |publisher=Bureau of Alcohol, Tobacco, Firearms, and Explosives |chapter-url=http://www.uaemt.org/uploads/explosives_plastics.pdf |access-date=15 July 2014 |chapter=Military Explosives |archive-date=19 July 2014 |archive-url=https://web.archive.org/web/20140719152211/http://www.uaemt.org/uploads/explosives_plastics.pdf |url-status=dead }}</ref>

The M112 demolition blocks of C-4 are commonly manufactured into the M183 "demolition charge assembly",<ref name=M15 /> which consists of 16 M112 block demolition charges and four priming assemblies packaged inside military Carrying Case M85. The M183 is used to breach obstacles or demolish large structures where larger [[satchel charge]]s are required. Each priming assembly includes a {{convert|5|or|20|ft|m|adj=on|spell=in}} length of detonating cord assembled with detonating cord clips and capped at each end with a booster. When the charge is detonated, the explosive is converted into compressed gas. The gas exerts pressure in the form of a shock wave, which demolishes the target by cutting, breaching, or cratering.<ref name="global" />

Other forms include the [[mine-clearing line charge]] and [[M18 Claymore mine|M18A1 Claymore Mine]].<ref name=bae />

=== Safety ===
{{Further|Explosives safety|Safety testing of explosives}}

Composition C-4 exists in the U.S. Army Hazardous Components Safety Data Sheet on sheet number 00077.<ref name="TM-9-1300-214">{{citation | url=http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf | title=Department of the Army Technical Manual – Military Explosives| author=Headquarters, U.S. Department of the Army | date=25 Sep 1990 | pages=A-13 (323)|postscript=.}}</ref>{{rp|323}} Impact tests done by the U.S. military indicate composition C-4 is less [[Sensitivity (explosives)|sensitive]] than composition C-3 and is fairly insensitive.  The insensitivity is attributed to using a large amount of binder in its composition.  A series of shots were fired at vials containing C-4 in a test referred to as "the rifle bullet test".  Only 20% of the vials burned, and none exploded.  While C-4 passed the Army's bullet impact and fragment impact tests at ambient temperature, it failed the shock stimulus, [[sympathetic detonation]] and [[shaped charge]] jet tests.<ref name="bae" /> Additional tests were done including the "pendulum friction test", which measured a five-second explosion temperature of 263&nbsp;°C to 290&nbsp;°C. The minimum initiating charge required is 0.2&nbsp;grams of [[Lead(II) azide|lead azide]] or 0.1&nbsp;grams of [[tetryl]]. The results of 100&nbsp;°C heat test are: 0.13% loss in the first 48 hours, no loss in the second 48 hours, and no explosions in 100 hours. The vacuum stability test at 100&nbsp;°C yields 0.2 cubic centimeters of gas in 40 hours. Composition C-4 is essentially [[Hygroscopy|nonhygroscopic]].<ref name="armymanual 8-111" />

The [[shock sensitivity]] of C-4 is related to the size of the nitramine particles. The finer they are the better they help to absorb and suppress shock. Using 3-nitrotriazol-5-one (NTO), or [[TATB|1,3,5-triamino-2,4,6-trinitrobenzene]] (TATB) (available in two particle sizes (5&nbsp;μm, 40&nbsp;μm)), as a substitute for RDX, is also able to improve stability to thermal, shock, and impact/friction stimulus; however, TATB is not cost-effective, and NTO is more difficult to use in the manufacturing process.<ref name="bae"/>

{| class="wikitable"
 |+ Sensitivity test values<br />{{nobold|reported by the U.S. Army.<ref name="TM-9-1300-214" />{{rp|311, 314}}}}
 |-
 | '''Impact''' test with 2 kilogram weight / PA APP (% TNT)
 | style="text-align:right;" |>100
 |-
 | '''Impact''' test with 2 kilogram weight / BM APP (% TNT)
 | {{NA}}
 |-
 | '''Pendulum friction''' test, percent explosions
 | style="text-align:right;" |0
 |-
 | '''Rifle bullet''' test, percent explosions
 | style="text-align:right;" |20
 |-
 | '''Explosion temperature''' test, Celsius
 | style="text-align:right;" |263 to 290
 |-
 | Minimum detonating charge, gram of [[lead azide]]
 | style="text-align:right;" |0.2
 |-
 | '''Brisance''' measured by Sand test (% TNT)
 | style="text-align:right;" |116
 |-
 | '''Brisance''' measured by plate dent test
 | style="text-align:right;" |115 to 130
 |-
 | Rate of '''detonation at density'''
 | style="text-align:right;" |1.59
 |-
 | Rate of '''detonation meters per second'''
 | style="text-align:right;" |8000
 |-
 | '''Ballistic pendulum''' test percent
 | style="text-align:right;" |130
 |}

== Analysis ==
=== Toxicity ===
C-4 has toxic effects on humans when ingested. Within a few hours multiple generalized seizures, vomiting, and changes in mental activity occur.<ref name="trippy">{{Cite journal|title = Toxic Effects Following Ingestion of C4 Plastic Explosive|last1 = Stone|first1 = William J.|date = December 1969|journal = Arch Intern Med|doi = 10.1001/archinte.1969.00300220078015|pages = 726–730|last2 = Paletta|first2 = Theodore L.|last3 = Heiman|first3 = Elliott M.|last4 = Bruce|first4 = John I.|last5 = Knepshield|first5 = James H.|issue = 6|volume = 124|pmid = 5353482}}</ref> A strong link to [[Central nervous system|central nervous]] dysfunction is observed.<ref>{{Cite journal|title = The Neurotoxicity of Cyclotrimethylenetrinitramine (RDX) in a Child: A Clinical and Pharmacokinetic Evaluation|last1 = Woody|first1 = Robert C.|date = 1986|journal = Clinical Toxicology|doi = 10.3109/15563658608992595|pmid = 3746987|pages = 305–319|last2 = Kearns|first2 = Gregory L.|issue = 4|volume = 24|last3 = Brewster|first3 = Marge A.|last4 = Turley|last5 = Sharp|first4 = Charles P.|first5 = Gregory B.|last6 = Lake|first6 = Robert S.}}</ref> If ingested, patients may be administered a dose of [[active charcoal]] to [[adsorb]] some of the toxins, and [[haloperidol]] intramuscularly and [[diazepam]] intravenously to help the patient control seizures until it has passed. However, ingesting small amounts of C-4 is not known to cause any long-term impairment.<ref name="yummy">{{cite journal | author1=K Fichtner, MD | title=A plastic explosive by mouth | date=May 2002 | journal=Journal of the Royal Society of Medicine | volume=95 | issue=5 | location=U.S. Army Hospital, Camp Bondsteel, Kosovo | pages=251–252 | quote=C4 contains 90% cyclotrimethylenetrinitramine (RDX) | doi=10.1177/014107680209500510| pmc=1279680 | pmid=11983768}}</ref>

=== Investigation ===
If C-4 is marked with a [[taggant]], such as [[DMDNB|DMNB]], it can be detected with an explosive vapor detector before it has been detonated.<ref name="MaterialsCouncil1998">{{cite book|author1=((Committee on Marking, Rendering Inert, and Licensing of Explosive Materials))|author2=((National Research Council))|author3=((Division on Engineering and Physical Sciences))|author4=((Commission on Physical Sciences, Mathematics, and Applications))|title=Containing the Threat from Illegal Bombings: An Integrated National Strategy for Marking, Tagging, Rendering Inert, and Licensing Explosives and Their Precursors|url=https://books.google.com/books?id=hgSdAgAAQBAJ&pg=PA160|date=27 May 1998|publisher=National Academies Press|isbn=978-0-309-06126-1|page=46}}</ref> A variety of methods for explosive residue analysis may be used to identify C-4. These include optical microscope examination and [[Scanning electron microscope|scanning electron microscopy]] for unreacted explosive, chemical spot tests, [[thin-layer chromatography]], [[X-ray crystallography]], and [[infrared spectroscopy]] for products of the explosive chemical reaction. Small particles of C-4 may be easily identified by mixing with thymol crystals and a few drops of [[sulfuric acid]]. The mixture will become rose colored upon addition of a small quantity of ethyl alcohol.<ref>{{cite web|last1=Allman, Jr.|first1=Robert|title=Explosives|url=http://chemstone.net/Forensics/Expl.html|website=chemstone.net|access-date=19 July 2014|archive-date=23 July 2014|archive-url=https://web.archive.org/web/20140723190157/http://chemstone.net/Forensics/Expl.html|url-status=dead}}</ref>

RDX has a high [[birefringence]], and the other components commonly found in C-4 are generally [[Isotropy|isotropic]]; this makes it possible for [[forensic science]] teams to detect trace residue on fingertips of individuals who may have recently been in contact with the compound.  However, positive results are highly variable and the mass of RDX can range between 1.7 and 130&nbsp;[[Nanogram|ng]], each analysis must be individually handled using magnifying equipment.  The [[Polarized light microscopy|cross polarized light]] images obtained from microscopic analysis of the fingerprint are analyzed with gray-scale thresholding<ref>{{cite web|last1=Brown |first1=Lew |title=Thresholding in Imaging Particle Analysis (A four part series) |url=http://www.particleimaging.com/wordpress/wp-content/uploads/2013/01/Thresholding_Series.pdf |website=www.particleimaging.com |publisher=ParticleImaging.com |access-date=19 July 2014 |url-status=dead |archive-url=https://web.archive.org/web/20150403104803/http://www.particleimaging.com/wordpress/wp-content/uploads/2013/01/Thresholding_Series.pdf |archive-date=3 April 2015 }}</ref> to improve contrast for the particles. The contrast is then inverted in order to show dark RDX particles against a light background. Relative numbers and positions of RDX particles have been measured from a series of 50 fingerprints left after a single contact impression.<ref name="fingerprints3">{{cite journal|last1 = Verkouteren|first1 = Jennifer R.|last2 = Coleman|first2 = Jessica L.|last3 = Cho|first3 = Inho|title = Automated Mapping of Explosives Particles in Composition C-4 Fingerprints|journal = Journal of Forensic Sciences|volume = 55|issue = 2|pages = 334–340|doi = 10.1111/j.1556-4029.2009.01272.x|pmid = 20102455|url = https://www.nist.gov/customcf/get_pdf.cfm?pub_id=831440|format=PDF|year=2010|s2cid = 5640135}}
</ref>

Military and commercial C-4 are blended with different oils. It is possible to distinguish these sources by analyzing this oil by high-temperature [[gas chromatography–mass spectrometry]]. The oil and plasticizer must be separated from the C-4 sample, typically by using a non-polar organic solvent such as pentane followed by [[solid phase extraction]] of the plasticizer on silica. This method of analysis is limited by manufacturing variation and methods of distribution.<ref name="atf"/>

== Use ==
=== Vietnam War ===
U.S. soldiers during the [[Vietnam War]] era would sometimes use small amounts of C-4 as a [[fuel]] for heating rations, as it will [[Deflagration|burn]] unless detonated with a [[Explosive#Primary explosive|primary explosive]].<ref name="fuelsource">{{Cite web | last1=Harris | first1=Tom | title=How C-4 Works | url=http://science.howstuffworks.com/c-42.htm | website=How Stuff Works | date=20 June 2002 | publisher=HowStuffWorks | access-date=14 July 2014}}</ref> However, burning C-4 produces poisonous fumes, and soldiers are warned of the dangers of personal injury when using the plastic explosive.<ref>{{Cite book | title=FM 3–34.214 (FM 5–250) Explosives and Demolitions | publisher=U.S. Department of the Army | location=Washington, D.C. | pages=6 | quote=Composition C4 explosive is poisonous and dangerous if chewed or ingested; its detonation or burning produces poisonous fumes. | chapter=Chapter 1: Military Explosives | date=27 August 2008 | chapter-url=http://info.publicintelligence.net/USArmy-Explosives.pdf }}</ref>

Among field troops in Vietnam it became common knowledge that ingestion of a small amount of C-4 would produce a "[[Substance intoxication|high]]" similar to that of ethanol.<ref name="yummy" /><ref name="trippy"/> Others would ingest C-4, commonly obtained from a [[M18 Claymore mine|Claymore mine]], to induce temporary illness in the hope of being sent on sick leave.<ref name="dispatches">{{Cite book | first=Michael | last=Herr | date=1977 | title=Dispatches | publisher=Knopf | isbn=978-0-679-73525-0 | url=http://www.abebooks.com/9780679735250/Dispatches-Herr-Michael-0679735259/plp}}</ref>

=== Use in terrorism ===
[[Terrorist group]]s have used C-4 worldwide in acts of [[terrorism]] and insurgency, as well as [[domestic terrorism]] and [[state terrorism]].

On May 13, 1985, the [[Philadelphia Police Department]] dropped [[1985 MOVE bombing|a C-4 bomb]] on the home of the [[MOVE organization]],<ref>{{Cite web |title=May 13, 1985: Philadelphia Police Bomb MOVE |url=https://www.zinnedproject.org/news/tdih/move-bombing/ |access-date=2024-05-13 |website=Zinn Education Project |language=en-US}}</ref> killing eleven people — including five children — and wiping out 61 homes in two city blocks.

Composition C-4 is recommended in [[al-Qaeda]]'s traditional curriculum of explosives training.<ref name="homelandpresentation"/> In October 2000, the group used C-4 to [[USS Cole bombing|attack the USS ''Cole'']], killing 17 sailors.<ref name="Guardian Bomb Type">{{cite news |url= https://www.theguardian.com/world/2003/aug/21/alqaida.iraq |title=Bomb type and tactics point to al-Qaida |last= Whitaker|first=Brian |date=21 August 2003 |work=The Guardian |access-date=July 11, 2009 | location=London}}</ref> In 1996, [[Hezbollah Al-Hejaz|Saudi Hezbollah]] terrorists used C-4 to [[Khobar Towers bombing|blow up the Khobar Towers]], a U.S. military housing complex in [[Saudi Arabia]].<ref>{{cite press release|url = https://www.fas.org/irp/news/2001/06/khobar.html|title = Attorney General, on Khobar Towers Indictment|last = Ashcroft|first = John|date = 21 June 2001}}</ref> Composition C-4 has also been used in [[improvised explosive device]]s by [[Iraqi insurgency (2003–11)|Iraqi insurgents]].<ref name="homelandpresentation"/>

===Gallery===
<gallery class="center">
File:Annual training 140820-N-AX577-063.jpg|Inserting a [[blasting cap]] into a block of C-4 to ready it for detonation
File:'Bomb Squad' uses tools, intelligence to battle terrorism 070801-F-4569G-203 2000456802.jpg|Wrapping on packaged C-4 indicate that it has been [[taggant|tagged]] for easier [[Explosive detection|detection]]. Even if no taggant is used, sophisticated forensic means can still be employed to identify the presence of C-4.
File:Eod2.jpg|Inserting [[blasting cap]]s into blocks of C-4 explosive (bottom) being used to destroy unexploded artillery components (cylinders)
File:US Navy 081212-N-1974P-016 Explosive Ordnance Disposal 2nd Class Jared Naegele, assigned to Explosive Ordnance Disposal Mobile Unit (EODMU) 1 builds an explosive charge intended to collapse a cave suspected of housing weapons c.jpg|A demolition charge being assembled from multiple sticks of C-4
</gallery>


== See also ==
{{div col|colwidth=30em}}
* [[Bomb]]
* [[Composition B]]
* [[Fuse (explosives)|Fuse]]
* [[Polymer-bonded explosive]]
* [[ANFO]]
* [[Semtex]]
* [[Use forms of explosives]]
{{div col end}}

== References ==
{{reflist|colwidth=30em}}

== External links ==
{{Commons category|C-4 explosive}}
* [https://science.howstuffworks.com/c-4.htm HowStuffWorks article] [https://web.archive.org/web/20220901213928/https://science.howstuffworks.com/c-4.htm Archived]
* ''[[The Anarchist's Cookbook|The Original Anarchist's Cookbook]]'' [https://archive.org/stream/TheAnarchistCookbook/anarchistcookbook2000_djvu.txt Ch. 137. "Reclamation of RDX from C-4 Explosives" by the Jolly Roger]
* [https://web.archive.org/web/20140727130407/http://www.pdfarchive.info/pdf/F/Fe/Fedoroff_Basil_T_-_Encyclopedia_of_Explosives_and_Related_Items_-_Vol_3_of_10_-_C_cont_to_D.pdf ''Encyclopedia of Explosives and Related Items'' Volume 3 (Archived)]
* ''[http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf Military Explosives TM 9-1300-214]'' [https://web.archive.org/web/20220819084946/http://www.lexpev.nl/downloads/tm91300214militaryexplosives.pdf Archived] 
* [https://cdn2.hubspot.net/hubfs/208537/assets/PDF/Product%20Sheets/NewWebsite_Munitions_CloseCombat_Demo%20Block%20M112.pdf American Ordnance M112 Demolition Block datasheet] [https://web.archive.org/web/20210724183316/https://cdn2.hubspot.net/hubfs/208537/assets/PDF/Product%20Sheets/NewWebsite_Munitions_CloseCombat_Demo%20Block%20M112.pdf Archived]
* [https://cdn2.hubspot.net/hubfs/208537/assets/PDF/Product%20Sheets/NewWebsite_Munitions_CloseCombat_Demo%20Block%20M183.pdf American Ordnance M183 Demolition Charge datasheet] [https://web.archive.org/web/20220217223658/https://cdn2.hubspot.net/hubfs/208537/assets/PDF/Product%20Sheets/NewWebsite_Munitions_CloseCombat_Demo%20Block%20M183.pdf Archived]
* [https://www.ebad.com/wp-content/uploads/2020/03/M112-Demolition-Block-released-1-22-20.pdf Ensign-Bickford M112 Demolition Block datasheet] [https://web.archive.org/web/20210724183004/https://www.ebad.com/wp-content/uploads/2020/03/M112-Demolition-Block-released-1-22-20.pdf Archived]
* [https://www.aesys.biz/_files/ugd/da7289_0a5266f58ce147c6b5e368ac83d96dcc.pdf Accurate Energetic Systems M112 Demolition Block datasheet] [https://web.archive.org/web/20220206060708/https://www.aesys.biz/_files/ugd/da7289_0a5266f58ce147c6b5e368ac83d96dcc.pdf Archived]

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[[Category:Explosives]]
[[Category:Weapons and ammunition introduced in 1956]]
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