Editing Taggant (section)

==Explosive taggants==

There are two types of taggant which have been considered for use with explosives.  One is to help detect the presence of a [[bomb]] in, for example, [[airport]] screening of [[luggage]]; and the other to assist the [[police]] in identifying the explosive after the [[detonation]] of such a bomb.

===Detection taggants===

These are [[Volatility (chemistry)|volatile]] [[chemical]]s which will slowly [[evaporate]] from the explosive and can be detected in the [[Earth's atmosphere|atmosphere]] by either [[detection dog]]s or specialised machines.  They are intended to enhance the detectability of the explosive by instruments or animals thus revealing the presence of a bomb containing the [[Explosive detection|explosive to be detected]]. Although various technologies exist to detect untagged explosives, detection taggants help to increase their reliability.  The inclusion of detection taggants in explosives is mandatory in some countries.  Following the bombing of [[Pan Am Flight 103|PanAm 103]] over Scotland, the International Civil Aviation Organization (ICAO) was instrumental in effecting a worldwide requirement for placing a detection taggant in plastic bonded explosives.

There is a choice between four possible detection taggant chemicals which must be added to [[plastic explosive]]s under the 1991 [[International Civil Aviation Organization]]'s [[Convention on the Marking of Plastic Explosives for the Purpose of Detection]]. In the [[United States]] the marker is always 2,3-dimethyl-2,3-dinitrobutane, usually called [[DMDNB]] or DMNB. [[Dog]]s are very sensitive to it and can detect as little as 0.5 parts per billion in the air, as can specialised [[ion mobility spectrometer]]s. Other taggants in use are [[ethylene glycol dinitrate]], known as EGDN and used to mark [[Semtex]], ortho-[[mononitrotoluene]] (o-MNT), and para-mononitrotoluene (p-MNT).

===Identification (or post detonation) taggants===

These have been considered for introduction in industrial explosives so that the manufacturer and batch number can be determined if they are used illegally.  The taggant must survive the detonation of the product and not be contaminated by the environment afterwards.  Several different technologies have been considered, but the most common are microscopic polymer/metallic particles.  Taggant evidence was crucial in the 1980 conviction of James L. McFillin in [[Maryland]] for the 1979 truck bombing murder of Nathan A. Allen, Sr.<ref>{{cite web|url=http://openjurist.org/713/f2d/57/united-states-v-l-mcfillin|title=UNITED STATES of America, Appellee, v. James L. McFILLIN, Appellant.|date=12 August 1981 |volume=F2d |issue=713 |page=57 |accessdate=October 29, 2014}}</ref>

A contention claimed for opposing mandated taggants is that most terrorist attacks use [[homemade explosive]]s (HME) which would allegedly not be tagged.  Examples given included, for instance, the [[1993 World Trade Center bombing]], the [[Oklahoma City bombing|Oklahoma City]] and the [[Omagh bombing]]s. Contamination of the site is also cited as a problem, since different taggants might be present at a crime scene from, for example, explosives used to obtain the building materials.

[[Switzerland]] passed a law in 1980 requiring taggants in explosives manufactured there, and that the code must be changed every six months.  So far it is the only country which requires identification taggants. Imported explosives must be tagged only if competing products are also manufactured in Switzerland.

In the United States, the [[National Rifle Association|NRA]] opposed the mandated use of taggants in firearm propellants after tests revealed a dangerous increase in burn rates. It was claimed that a chemical incompatibility with the propellent powders would cause such an increase in pressures that many firearms would burst after using a taggant-laced powder that had been stored for as little as several months. However, these tests were performed on gunpowder with a taggant concentration of 500,000 parts per million (in other words, one-half), which is 2,000 times greater than the official recommended taggant concentration of 250 parts per million.<ref>[http://www.abc.net.au/science/articles/1999/08/06/42124.htm Tagging Explosives], ''[[ABC Science]]'', Karl S. Kruszelnicki, August 6, 1999. Retrieved 31 May 2016.</ref>