Wednesday, June 08, 2011

The Explosives And The Contaminated Samples

I wasn't intending to write any more on this blog about the issue of the explosives used in the train bombings, I've already covered the issue in some detail before and there have been no significant developments. But then a couple of days ago a Google Alert I have set for news on the Madrid bombings caught my eye, and I found something that potentially sheds light on a genuine mystery to do with the analysis of the explosives used in the bombs.

When the analysis of the samples recovered from the bomb sites and other locations associated with the attacks was carried out for the trial, some curious results were returned. Traces were found of substances that are not present in the dynamite which was used in the train bombs, Goma-2 Eco. The conspiracy theorists have made a great deal of these unexpected findings, indeed their whole case that a different explosive was used in the attacks is based around this data. In particular, they have used the detection of nitroglycerine in one sample from one of the bombed trains to argue that the explosive used must have been Titadine, and in the process keeping alive the allegation that ETA were somehow involved in the bombings. Nitroglycerine is not a component of Goma-2 Eco and is for at least one type of Titadine, an explosive often used by ETA in the past.

Another substance not present in Goma-2 Eco but which is a component of Titadine, dinitrotoluene (DNT), was also detected in the same sample. A problem for the conspiracy theorists, however, has always been the fact that the same substance was also revealed in the tests on samples of Goma-2 Eco that were recovered from different sites connected with the bombings. No definitive explanation was ever established at the time of the trial for what appeared to be some kind of contamination of the samples. Suggestions were made that contamination could have occurred in the factory, in the Asturian mine where the explosives used were stolen, or in the storage facilities used by the police. 

The conspiracy theorists would have none of this, as any credible theory of contamination wrecks their insistence on Titadine having been used in the bombs. Numerous pages of El Mundo and even a whole book have been produced all based around the slender proposition that a tiny trace of nytroglycerine proves their theory. But then the only explanation they have been able to offer for the contamination of the other samples has been that someone sneaked into the place where the explosives samples were being held and deliberately contaminated them! Evidence for this assertion? Don't ask, we're back in the territory of imagination.

All of this brings me to the reason for this new post. In the real world of science where theories are tested there has been some interesting work done. The study described in this link has tested whether any cross-contamination could occur between explosives samples held in polyethylene bags at the police storage facility. The results, which included tests with DNT, have demonstrated that volatile components of explosives can escape from these bags. Not only that, but traces of these components over time can enter into other bags containing different substances. 

The importance of this study is twofold. Firstly, it suggests that the storage method used by the police at the time of the bombings was not sufficiently secure as samples of different explosives could have been held in the same place and cross-contamination could occur. Secondly, it might be the explanation for why substances like DNT were not identified in the samples immediately following the bombings, but did show up in the tests carried out 3 years later for the trial. Presumably the tests carried out by the scientists for this research are reproducible and therefore verifiable. Precisely the kind of test that those who still persevere with more bizarre explanations will be keen to avoid. 

No comments: