On Wednesday August 4th a large amount of ammonium nitrite fertilizer exploded in Beirut near the centre of the city, killing around a hundred people and wounding thousands. In a warehouse in the harbour area about three thousand tons of the material blew up, comparable to the two largest ever man-made (non-nuclear) explosions, 1917 at Oppau in Germany and at Texas City in 1947. Despite Beirut’s dreadful recent history, and the local presence of Hezbollah and other terrorists, the disaster seems likely to have been caused by incompetence rather than malice.
This is in contrast to some more recent and much smaller bangs. On Patriots’ Day, April 16th, 2013, in Boston, two bombs were exploded killing three people and wounding many others. A day later, in West, Texas, a fire at the West Fertilizer Company led to an explosion which killed ten people and destroyed half the town. A coincidence? Maybe the two Boston Chechens had accomplices a few thousand miles away in Texas who planned a follow-up, or perhaps two groups of terrorists came to the independent conclusion that it was a good time to try something.
Back in 2001, two planes flew into the World Trade Center and killed about three thousand people. Ten days later, at the AZF fertiliser factory in Toulouse, an explosion caused 29 deaths and 2442 injuries. Another strange coincidence? The AZF factory in Toulouse had two to three hundred tons of ammonium nitrate, a common nitrogenous fertiliser, and it was that which exploded. It is also used in explosive compositions, and can be made, with some difficulty, to explode on its own.
In the late fifties I visited a fertiliser factory in Essex, which produced ammonium nitrate. Liquid ammonia was produced from natural gas in a refinery next-door, piped through the fence, and stored in a spherical steel tank. Some of the ammonia was oxidised using a platinum gauze catalyst, to prepare nitric acid, which was combined with more ammonia to produce ammonium nitrate. The fertilizer factory that exploded in West Texas is reported
to have had a storage tank holding 20 tons of ammonia, and about 200 tons of ammonium nitrate in store.
There have been two major accidental explosions involving the fertilizer. In 1921, at Oppau, near Mannheim in Germany, BASF had a dump of about 4,500 tons of a 50/50 mixture of ammonium nitrate and ammonium sulphate. The storage piles had caked hard, so they broke them up with explosives.
On 21 September the whole dump blew up, and 430 people were killed. On 16 April 1947, in the docks at Texas City, a fire broke out on the freighter Grandcamp, which had been loaded with 3,130 tons of ammonium nitrate. The captain decided to smother the fire with steam, causing the whole cargo to blow up killing 576 people, and destroying Texas City.
Clearly the likely behaviour of ammonium nitrate is not mysterious. The explosion near Mannheim is believed to have been the biggest man-made (non-nuclear) explosion ever. Anhydrous (liquid) ammonia is inflammable. If it leaks from a tank, it evaporates and the mixture with air can be very inflammable, though ammonia is lighter than air, and has a very strong, noticeable smell. It seems more likely that the ammonium nitrate exploded, though it is not very easy to detonate.
What do we make of this in relation to Boston? The bombers may have used ammonium nitrate but they probably relied on old-fashioned gunpowder, a mixture of potassium nitrate, charcoal and sulphur, the latter two can be bought over the counter, packed into a pressure cooker with ball bearings. An alternative could have been what the IRA called ‘Co-Op Mix’, ammonium nitrate and cooking oil. On the other hand setting off the explosion in West Texas would have required a relatively sophisticated timer.
What was used is significant. Experts believe people such as the Boston bombers consist of small numbers of self-radicalising young men isolated even within their own Moslem communities. For example Chechens living in America. This was true of the 9/11 bombers who ……‘were not ‘recruited’ by Al Qaeda. They were Middle eastern Muslims isolated even among the Moroccan and Turkish Muslims who predominate in Germany.’… three wound up living together as they self-radicalized’* The same is true of the 7/7 bombers in London.
The popular view of a worldwide network of support for such groups supplying them with the latest equipment is erroneous. The bombs used are crude, made from over the counter materials and it is impossible to stop anybody buying them. The real detonator is between a bomber’s ears. Its primer is a cascade of foolish liberal excuses by the left for the murderous excesses of Islam. That the Americans are behind every bombing, that they ‘oppress’ Arab States when the latter need no lessons in oppression. As long as such nonsense is believed we will have ‘over the counter’ bombers.
(* Testimony before the House Appropriations Subcommittee on Homeland Security Washington, DC, March 12, 2008.)
Robin Cave is a retired chemist