Brussels attack: Explosive used by bombers a chemical nightmare

People hold a banner that reads “not on behalf of Islam” as they gather to pay tribute to the victims of the terror attacks on Place de la Bourse square in Brussels on Friday. (Photo: AFP)

An empty apartment block on a quiet street turned out to be the perfect place for the three suspected Brussels attackers to prepare the home-made nail bombs used in Tuesday’s airport and metro attacks that killed at least 31 people.

In a building undergoing renovation, there were no near neighbours to notice them taking in large quantities of strong-smelling household chemicals, as well as a suitcase of nails, to concoct an unstable white explosive powder known as TATP, or triacetone triperoxide, that they later used in their attacks.

“Even if someone had st-opped them, they could ha-ve said the materials were for renovation,” said Hass-an Abid, an official at the local town hall, who was trying to determine why authorities had no knowledge of the men living illegally on the fifth floor.

Having moved in two mo-nths ago, the Belgian brot-hers Khalid and Brahim El Bakraoui used the apartment in the largely middle class borough of Schaer-beek as a laboratory-cum-hideout, from where Brahim and two other men took a taxi on Tuesday morning to the airport to commit their attacks.

Their choice of low-cost explosives — among ingredients are drain cleaner and nail varnish remover — apparent knowledge of chemistry and ability to set up in an apartment 15 minutes drive from the airport should offer clues about ISIS bombmaking methods to investigators struggling to understand how the Syria-based group built a violent network of radicalised young Belgians.

The ready availability of ingredients, compared to military explosives favoured by older militant groups like the IRA in Northern Ireland or Basque separatists ETA in Spain, highlights the risks across Europe of more big attacks.

TATP is a highly volatile explosive. Palestinian insurgents who experimented with it in the 1980s nicknamed it “the mother of Satan” because the white crystal powder can be easily detonated by a cigarette, a match or too much heat.

However, the need for premises to manufacture quantities of TATP over several weeks and the final mixture’s “use by” date of just a few days make the bombmakers vulnerable to the intensive search efforts of detectives on their trail.