TA-ANALYSIS: Thermobaric bombs and fertilisers

Preparing for the Worst: If Terrorist get their hands on thermobaric bombs protecting people and buildings will be even harder. Some expert's fear that terrorists are trying to develop thermobaric and fuel-air bombs which can be even more devastating than conventional devices.

The Canadian defence research and development agency DRDC is taking the threat so seriously that it is testing thermobaric devices itself in an attempt to develop defences against them. And the US Marine Corps is using computorised war games to devise tactics that could help minimise casuaties if insurgents in countrys such as Iraq use thermobaric attacks. The devices use a small charge to generate a cloud of explosive mixed with air .the main explosion is then detonated by a seconed charge (a fule-air explosion),or by the explosive reacting spontaneously with air (a thermobaric explosion).

The resulting shock wave is not as strong as a conventional blast ,but it can do more damage as it is more sustained and ,crucially, diminishes far more gradually with distance .The main explosion is followed by a partial vacuum, creating a suction effect that compounds the damage and can add to the injuries-hence the term vacuum bomb. In enclosed spaces, the devices also use up oxygen and produce choking fumes, suffocating any survivors of the initial blast.

Numerous industrial accidents attest to the power of thermobaric explosions-a massive blast in Iran this year has been blamed on a fuel-air explosion after a train carrying petrol derailed.The soviet Union developed a wide range of thermobaric weapons, which were used by Russia in the Chechnya campaign of 1999.A US Marine Corps study, based on interviews with Russian officers and Chechens, concluded that they were capable of killing troops in bunkers and destroying buildings that hadn�t been reinforced.�Walls and surfaces do not necessarily shield victims,� notes a US training manual.

This prompted the US to rush out the BLU-118 �cave buster� for use in Afghanistan in 2001, More thermobaric devices have been developed since, such as a new �Hellfire� anti tank missile used in Iraq. These weapons were widely publicised.� A thermobaric Hellfire missile can take out the first floor of a building without damaging the floors above,� the US Secretary of Defence, Donald Rumsfeld, told a press briefing on 14 May 2003,�it is capable of reaching around corners, striking enemy forces that hide in caves or bunkers.�

These are signs that terrorist too are trying to create thermobaric weapons. For instance, in 2002 a tanker truck was used in a suicide attack on a synagogue in Tunisia, thought to be the work of AL-Qaida.Some experts think the way the fuel tanks were rigged with explosives shows a knowledge of fuel-air explosive techniques.

Designs for a fuel-air device were also acquired by the CIA from three alleged IRA members on trail in Colombia .The three are said to have been developing the bomb in conjunction with the country�s FARC guerrilla group.� Although as IRA/AL Qaida collaboration seem unlikely, the bottom line is that their respective manuals are probably in circulation,� says David Ritzel, an explosive expert working for the DRDC. Defending buildings against such an attack would be extremely difficult. The deadliest conventional car bomb attacks have been those where the attacker succeeded in getting a vehicle packed with explosives very close to the target To prevent this, concrete barriers have been placed around many buildings regarded as potential targets. But the barriers would have to be much further away than at present to provide the same level of protection against fuel-air devices of a similar size.

However, creating such devices poses far more technical challenges than making conventional bombs, says Stephen Murray, head of the DRDC�s threat assessment group. Their aim is to develop software to predict how buildings will respond to thermobaric blasts and help design fortifications. Even small mistakes in the design or choice of materials can prevent fuel-air devices working, Murray says. Unfortunately, terrorists could simply buy off �the �shelf thermobaric weapons on the black market� The Russians have used shmel rocket launchers with thermobaric warheads for many years. They have turned up in the hands of the Cobra militia in the Democratic Republic of Congo, for instance. The US Department of state has also accused one arms company of illegally supplying thermobaric weapons like these to both Iran and Iraq �a charge it has denied.

Western countries are developing similar weapons. The US created a bazooka with a thermobaric warhead called the SMAW-NE for the war in Iraq. China recently unveiled its own version, and to be working on one although the defence ministry insists that it is merely an �enhanced weapon�.

Written by David Hambling
New Scientist issue: 20 March 2004

Related Sources of Interest
How thermobaric bombs work
Thermobaric weapon
Bunker busters enter action in Afghanistan
Fuel/Air Explosive (FAE)

Making Bomb-building harder for terrorist

Vigilance and intelligence will always be the best way weapon against terrorism. But it may be possible to make it harder for terrorist to turn on readily available chemical into bombs.

Ammonium nitrate, a widely used fertilizer, has been used in several IRA attacks the World Trade Center bombing in New York in 1993, the Oklahoma City bombing in 1995 and the Bali bombing in 2002.

Millions of tonnes of ammonium nitrate are produced each year for the use as a fertiliser. Mining companies turn small quantities into an explosive by mixing the chemical with fuel oil. While it is not necessarily easy for would-be bombers to do this with fertiliser-grade ammonium nitrate, it is not impossible.

Now Speciality Fertilizer Products a company based in Belton Missouri is patenting a water-soluble polymer coating for the fertilizer granules that repels fuel oil .The coating dissolves rapidly in soil, so it would not interfere with ammonium nitrate�s main function as a fertiliser. If it works and is widely adopted. The treatment could make it harder for terrorists to turn fertiliser-grade ammonium nitrate into bombs, and could also help prevent industrial accidents.

We have done infiltration tests that show that the oil does not get into the ammonium nitrate,� says company founder Larry Sander. That should at least reduce the force of any explosion that did occur. He is now sending the product to labs for tests. The cost of the coating would depend on how widely manufacturers adopt the technology, Sanders Says not everyone is convinced, however. One expert, said that the polymer might react with ammonium nitrate under the high temperatures and intense pressures that follow the initial pressures that follow the initial detonation, perhaps even providing additional energy for an explosion. But other groups are also working on ways of making ammonium nitrate less explosive.� There�s lots of research going on,�says Jimmie Oxley, an explosives expert at the university of Rhode Island in Kingston.� it is way too sensitive to talk about.�

Most countries, including the US and Australia, do not regulate the sale of fertiliser � grade ammonium nitrate, but in the European Union it is already tightly restricted.� we are all aware of the sensitivities.� says David Heather of the Agricultural industries Confederations in Peterborough, UK. Anything sold as a fertiliser must pass a detonation resistance test that determines how well the product resists an explosion. In the EU, fertiliser-grade ammonium nitrate is actually, manufactured to higher standards than the explosive grade, with large, dense granules to prevent them absorbing fuel oil. Stabilisers are sometimes added to prevent the granules breaking down.

Another approach is to mark fertilisers so that that any bomb can at least be tracked back to its source. Authentix of Dallas, Texas, says its can chemically tag any fertiliser during manufacturing. In the case of ammonium nitrate, molecules that contain different isotopes of nitrogen and hydrogen can be added in concentrations of parts per billion.� We can pick up traces of that marker in the explosive up to five kilometres away after an explosion,� says Ian Eastwod at Authentix�s UK office.
Microtrace of Minneapolis, Minnesota, makes mircoplastic barcodes that�s can be added to fertiliser. These barcodes can survive explosions and can uniquely identify up to 37 million products. However while such technologies have long been available, they have yet to be adopted by fertiliser manufactures.

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Written by Anil Ananthaswamy
New Scientist issue: 20 March 2004
Related Sources of Interest
Agricultural Industries Confederation, UK
Authentix, Dallas
Microtrace, Minneapolis
valhall Missing Fertilizer.





[edit on 9/10/2004 by SE7EN]

Bump due to the tie-in to my article about the missing fertilizer!