Mumbai: The three bombs that exploded on July 13 contained a cocktail of TNT, ammonium nitrate, nitrite and petroleum hydrocarbon, according to the final report of the state Forensic Science Laboratory (FSL) at Kalina. Trinitrotoluene, or TNT, was the main explosive in the bombs that went off at Zaveri Bazaar, Opera House and Dadar, killing 27 people.
Earlier, there were reports that RDX or pentaerythritol tetranitrate (PETN) could have been the main explosive in the bombs. “Neither RDX nor PETN were used in these bombs,” said an Anti-Terrorism Squad (ATS) officer. He added that the bombs seemed to follow an older pattern. TNT, a yellow solid, is sometimes used as a reagent in chemical synthesis, but it is best known as an explosive. The Zaveri Bazar and Opera House bombs weighed around 2.5 to 3 kg while the bomb set off near the Dadar railway station was around 1.5 kg. The Mumbai bombs appear different from the one set off outside the Delhi high court earlier this month, as initial reports said that bomb had PETN.
However, it is not the TNT but ammonium nitrate that points to a sinister pattern. Ammonium nitrate was earlier used in three 2003 blasts (in a BEST bus at Ghatkopar, Mulund and Vile Parle), the 2006 11/7 serial train blasts, the 2008 Jaipur blasts and the 2010 German Bakery blast in Pune.
After the 13/7 blasts, concerned over the increased use of ammonium nitrate by terror groups, the government declared the chemical as an “explosive”. But given the widespread use of the mixture as fertilizer, the government notification came with a rider – its possession and use can invoke penal action only if 45% or more of a particular composition has ammonium nitrate. Ammonium nitrate is easily available in stores that stock industrial fertilizers. It costs a mere Rs 50 per kg. It is easily available in chemical shops and also used as an oxidizing agent in laboratories. When mixed with a hydrocarbon, it becomes part of a potent explosive mixture.
The Times of India, September 29, 2011