Nails and nail varnish: Brussels bombers prepared a 'satanic' cocktail

TATP Explosives Likely Used in Brussels Attacks

BRUSSELS (Reuters) -- 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.

READ MORE: Brussels attacks survivor Mason Wells speaks out

In a building undergoing renovation, there were no near neighbors 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.

RELATED: Memorials following the deadly blasts in Brussels

45 PHOTOS
Memorials in Brussels after attacks
See Gallery
Nails and nail varnish: Brussels bombers prepared a 'satanic' cocktail
Young women hold each other at a makeshift memorial in front of the stock exchange at the Place de la Bourse (Beursplein) in Brussels on March 22, 2016, following triple bomb attacks in the Belgian capital that killed about 35 people and left more than 200 people wounded. A series of explosions claimed by the Islamic State group ripped through Brussels airport and a metro train on March 22, killing around 35 people in the latest attacks to bring bloody carnage to the heart of Europe. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
TOPSHOT - A photo taken on March 22, 2016 shows a sign peace made of candles in front of the Bourse of Brussels in tribute to the victims of Brussels following triple bomb attacks in the Belgian capital that killed about 35 people and left more than 200 people wounded. Belgium launched a huge manhunt on March 22 after a series of bombings claimed by the Islamic State group ripped through Brussels airport and a metro train, killing around 35 people in the latest attack to bring carnage to the heart of Europe. / AFP / BELGA / Aurore Belot / Belgium OUT (Photo credit should read AURORE BELOT/AFP/Getty Images)
TOPSHOT - People light candles in tribute to victims at a makeshift memorial in front of the stock exchange at the Place de la Bourse (Beursplein) in Brussels on March 22, 2016, following triple bomb attacks in the Belgian capital that killed about 35 people and left more than 200 people wounded. A series of explosions claimed by the Islamic State group ripped through Brussels airport and a metro train on March 22, killing around 35 people in the latest attacks to bring bloody carnage to the heart of Europe. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: A young girl lights a candle at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
TOPSHOT - People stand hand in hand in tribute to victims at a makeshift memorial in front of the stock exchange at the Place de la Bourse (Beursplein) in Brussels on March 22, 2016, following triple bomb attacks in the Belgian capital that killed about 35 people and left more than 200 people wounded. A series of explosions claimed by the Islamic State group ripped through Brussels airport and a metro train on March 22, killing around 35 people in the latest attacks to bring bloody carnage to the heart of Europe. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather to leave tributes at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
A message written on the ground reads 'Brussels is beautiful' next to flowers and candles following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People gather at Place de la Bourse in support of the victims after the terrorist attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Aurelien Meunier/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People light candles at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People hold up a banner as a mark of solidarity at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: Candles are lit at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
A placard reads 'Share your love' at a makeshift memorial following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
A woman reads messages written on the ground at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
People walk over messages written on the ground at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
People leave candles and flowers in tribute to victims of triple bomb attacks in front of the stock exchange building in the city center of Brussels on March 22, 2016. A series of apparently coordinated explosions ripped through Brussels airport and a metro train, killing at least 26 people in the latest attacks to target Europe. / AFP / Belga / NICOLAS MAETERLINCK / Belgium OUT (Photo credit should read NICOLAS MAETERLINCK/AFP/Getty Images)
People leave messages and flowers in tribute to victims of triple bomb attacks in front of the stock exchange building in the city center of Brussels on March 22, 2016. A series of apparently coordinated explosions ripped through Brussels airport and a metro train, killing at least 26 people in the latest attacks to target Europe. / AFP / Belga / NICOLAS MAETERLINCK / Belgium OUT (Photo credit should read NICOLAS MAETERLINCK/AFP/Getty Images)
People gather around a makeshift memorial at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
A placard reads share your love next to flowers and candles laid on the ground following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
A heart in the colours of the Belgian flag is taped onto a bag as people gather around a makeshift memorial following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
People write messages on the ground at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
A man writes the word 'Peace' in different languages at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
A replica of the Manneken Pis statue stands at a makeshift memorial at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
People hold hands as they gather at a makeshift memorial at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
People hold hands as they gather at a makeshift memorial at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
People light candles at a makeshift memorial at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
A replica of the Manneken Pis statue is placed among candles at a makeshift memorial at Place de la Bourse (Beursplein) following attacks in Brussels on March 22, 2016. Airlines cancelled hundreds of flights and European railways froze links with Brussels after a series of bomb blasts killed around 35 people in the city's airport and a metro train, sparking a broad security response. AFP PHOTO / KENZO TRIBOUILLARD / AFP / KENZO TRIBOUILLARD (Photo credit should read KENZO TRIBOUILLARD/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: People walk across slogans written on the ground in chalk saying 'Brussels, Belgium, Today' at Beursplein sqaure following todays attack on March 22, 2016 in Brussels, Belgium. At least 34 people are thought to have been killed after Brussels airport and the Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. on March 22, 2016 in Brussels, Belgium. (Photo by Alexander Koerner/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: A painting is left as a tribute at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: A message is written on a wall following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: Flowers are placed into the mouth of a lion statue as people gather to leave tributes at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: A candle is lit as people gather to leave tributes at the Place de la Bourse following today's attacks on March 22, 2016 in Brussels, Belgium. At least 31 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

"Even if someone had stopped them, they could have said the materials were for renovation," said Hassan 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.

Belgian investigators do not answer questions on the case.

Having moved in two months ago, the Belgian brothers Khalid and Brahim El Bakraoui used the apartment in the largely middle class borough of Schaerbeek 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 IS bombmaking methods to investigators struggling to understand how the Syria-based group built a violent network of radicalized young Belgians.

RELATED: International response to the Brussels attacks

5 PHOTOS
Brussels Attacks: International security response
See Gallery
Nails and nail varnish: Brussels bombers prepared a 'satanic' cocktail
PARIS, FRANCE - MARCH 22: (FRANCE OUT) French police officers patrol at the Trocadero Plaza next to the Eiffel Tower on March 22, 2106 in Paris, France. Since this morning 400 policemen and gendarmes have been deployed to increase the security in airports, stations and public transportation around Paris and its region after the terrorist attacks in Brussels today. (Photo by Christophe Morin/IP3/Getty Images)
PARIS, FRANCE - MARCH 22: (FRANCE OUT) French police officers patrol at the Trocadero Plaza next to the Eiffel Tower on March 22, 2106 in Paris, France. Since this morning 400 policemen and gendarmes have been deployed to increase the security in airports, stations and public transportation around Paris and its region after the terrorist attacks in Brussels today. (Photo by Christophe Morin/IP3/Getty Images)
PARIS, March 22, 2016-- Police officers patrol at Charles de Gaulle airport in Paris, capital of France, March 22, 2016. Security has been beefed up in France with 1,600 police officers deployed at airports, railway stations and bus stations since the attacks on Brussels Tuesday. (Xinhua/Theo Duval via Getty Images)
BUDAPEST, HUNGARY - MARCH 22: Hungarian counter-terrorism agents secure the Liszt Ferenc International Airport in Budapest, Hungary on March 22, 2016 following high level security alert following the morning explosions in Brussels. At least 34 people were killed and more than 100 injured in multiple explosions at an airport and metro station in Brussels on today's morning. (Photo by Arpad Kurucz/Anadolu Agency/Getty Images)
HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

The ready availability of ingredients, compared to military explosives favored 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.

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. French and Belgian police have successfully found and neutralized bomb "factories," most recently in the Paris suburb of Argenteuil on Thursday.

Militants have used fake identities and premises listed with municipal authorities as unoccupied to evade residency checks.

Brussels police failed to find the Schaerbeek flat in time, but were there shortly after the attacks, aided by the taxi driver who unwittingly took the three men to the airport.

Prosecutors uncovered 15 kg (33 lb) of TATP, as well as 180 liters of the chemicals needed to make bombs.

RELATED: Scenes of destruction following the Brussels attacks

35 PHOTOS
Brussels Attacks: Explosions at airport, Maelbeek metro station
See Gallery
Nails and nail varnish: Brussels bombers prepared a 'satanic' cocktail
People are evacuated from Brussels Airport, in Zaventem, on March 22, 2016. after at least 13 people have been killed by two explosions in the departure hall of Brussels Airport. / AFP / Belga / VIRGINIE LEFOUR / Belgium OUT (Photo credit should read VIRGINIE LEFOUR/AFP/Getty Images)
#BREAKING: Two loud explosions at #Zaventem airport in #Brussels https://t.co/JFw9RGLjnh
This video footage captures the aftermath of the explosions at Zaventem airport, #Brussels https://t.co/wcsNygh91Y
Brussels aftermath video shows survivors huddled together, telling one another: "It's okay". https://t.co/3Y7lEXrrjP https://t.co/KdqFXR9Wft
BRUSSELS, BELGIUM - MARCH 22: Passengers are evacuated from Zaventem Bruxelles International Airport after a terrorist attack on March 22, 2016 in Brussels, Belgium. At least 13 people are though to have been killed after Brussels airport was hit by two explosions whilst a Metro station was also targeted. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Sylvain Lefevre/Getty Images)
A private security guard helps a wounded women outside the Maalbeek metro station in Brussels on March 21, 2016 after a blast at this station located near the EU institutions. Belgian firefighters said at least 26 people had died after 'enormous' blasts rocked Brussels airport and a city metro station today, as Belgium raised its terror threat to the maximum level. / AFP / Michael VILLA (Photo credit should read MICHAEL VILLA/AFP/Getty Images)
A picture taken on March 22, 2016 shows a Belgian police vehicle driving past passengers who are evacuating the Brussels Airport of Zaventem. At least 13 people were killed and 35 injured as twin blasts rocked the main terminal of Brussels airport on March 22, 2016, Belgian media quoted the federal prosecutor as saying. Officials were not immediately available to confirm the figure when contacted by AFP. The federal police earlier confirmed one death. / AFP / Belga / Jonas Roosens / Belgium OUT (Photo credit should read JONAS ROOSENS/AFP/Getty Images)
A picture taken on March 22, 2016 shows a Belgian police vehicle driving past passengers who are evacuating the Brussels Airport of Zaventem. At least 13 people were killed and 35 injured as twin blasts rocked the main terminal of Brussels airport on March 22, 2016, Belgian media quoted the federal prosecutor as saying. Officials were not immediately available to confirm the figure when contacted by AFP. The federal police earlier confirmed one death. / AFP / Belga / Jonas Roosens / Belgium OUT (Photo credit should read JONAS ROOSENS/AFP/Getty Images)
A picture taken on March 22, 2016 shows smoke rising from the Maalbeek underground, in Brussels, following a blast at the station close to the capital's European quarter. The Brussels metro service was being shut down on March 22, its operator said. The measure came after a rush-hour explosion at Maalbeek station with TV images showing black smoke pouring from the station entrance. / AFP / Belga / Seppe KNAPEN / Belgium OUT (Photo credit should read SEPPE KNAPEN/AFP/Getty Images)
A security perimeter has been set, on March 22, 2016 near Maalbeek metro station in Brussels, after a blast at this station near the EU institutions caused deaths and injuries. AFP PHOTO / EMMANUEL DUNAND / AFP / EMMANUEL DUNAND (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: Broken glass and blood is seen beside signage outside an entrance to Maelbeek metro station following todays attack on March 22, 2016 in Brussels, Belgium. At least 34 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
BRUSSELS, BELGIUM - MARCH 22: Broken glass is seen outside an entrance to Maelbeek metro station following todays attack on March 22, 2016 in Brussels, Belgium. At least 34 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels. (Photo by Carl Court/Getty Images)
Policemen stand guard at the entrance of a security perimeter set near Maalbeek metro station, on March 22, 2016 in Brussels, after a blast at this station near the EU institutions caused deaths and injuries. AFP PHOTO / EMMANUEL DUNAND / AFP / EMMANUEL DUNAND (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)
Rescue teams evacuate wounded people outside the Maalbeek metro station in Brussels on March 22, 2016 after a blast at this station located near the EU institutions. Belgian firefighters said at least 26 people had died after 'enormous' blasts rocked Brussels airport and a city metro station today, as Belgium raised its terror threat to the maximum level. / AFP / - (Photo credit should read -/AFP/Getty Images)
Passengers evacuated after blast at #Maalbeek metro station in #Brussels via @EurActiv https://t.co/O3W8C2rpPm https://t.co/XmIoeKfE9F
People are evacuated from Brussels airport in Zaventem on March 22, 2016 following twin blasts. A string of explosions rocked Brussels airport and a city metro station, killing at least 21 people in apparently coordinated attacks, officials said. == BELGIUM OUT == / AFP / Belga / DIRK WAEM / Belgium OUT (Photo credit should read DIRK WAEM/AFP/Getty Images)
A man with blood stains on his sweater leaves Brussels airport in Zaventem on March 22, 2016 following twin blasts. A string of explosions rocked Brussels airport and a city metro station, killing at least 21 people in apparently coordinated attacks, officials said. == BELGIUM OUT == / AFP / Belga / DIRK WAEM / Belgium OUT (Photo credit should read DIRK WAEM/AFP/Getty Images)
Amateur footage shows scene at #Brussels airport after explosions (video: Bart van Meele) https://t.co/v29k9dvMiM
Passengers are evacuated from Brussels airport, on March 22, 2016 in Zaventem, after at least 13 people were killed and 35 injured as twin blasts rocked the main terminal of Brussels airport.AFP PHOTO / JOHN THYS / AFP / JOHN THYS (Photo credit should read JOHN THYS/AFP/Getty Images)
A victim receives first aid by rescuers, on March 22, 2016 near Maalbeek metro station in Brussels, after a blast at this station near the EU institutions caused deaths and injuries. AFP PHOTO / EMMANUEL DUNAND / AFP / EMMANUEL DUNAND (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)
A victim receives first aid by rescuers, on March 22, 2016 near Maalbeek metro station in Brussels, after a blast at this station near the EU institutions caused deaths and injuries. AFP PHOTO / EMMANUEL DUNAND / AFP / EMMANUEL DUNAND (Photo credit should read EMMANUEL DUNAND/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22 : Police officers stand guard around the Zaventem Airport after two explosions went off in Brussels, Belgium on March 22, 2016. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)
BRUSSELS, BELGIUM - MARCH 22 : Police officers stand guard around the Zaventem Airport after two explosions went off in Brussels, Belgium on March 22, 2016. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)
Passengers are gathered, on March 22, 2016 near Brussels airport in Zaventem, following its evacuation after at least 13 people were killed and 35 injured as twin blasts rocked the main terminal of Brussels airport.AFP PHOTO / JOHN THYS / AFP / JOHN THYS (Photo credit should read JOHN THYS/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22 : Police officers stand guard around the Zaventem Airport after two explosions went off in Brussels, Belgium on March 22, 2016. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)
Firefighters arrive at a security perimeter set in the Rue de la Loi near the Maalbeek subway station, in Brussels, on March 22, 2016, after an explosion killed around 10 people, according to spokesman of Brussels' fire brigade A string of explosions rocked Brussels airport and a city metro station on Tuesday, killing at least 13 people, according to media reports, as Belgium raised its terror threat to the maximum level. / AFP / Belga / LAURIE DIEFFEMBACQ / Belgium OUT (Photo credit should read LAURIE DIEFFEMBACQ/AFP/Getty Images)
Passengers who were evacuated from the airport wait in Zaventem, on March 22, 2016, after a string of explosions rocked Brussels airport of Zaventem and a city metro station, killing at least 13 people, according to media reports, as Belgium raised its terror threat to the maximum level. / AFP / Belga / SEPPE KNAPEN / Belgium OUT (Photo credit should read SEPPE KNAPEN/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22 : Police officers stand guard around the Zaventem Airport after two explosions went off in Brussels, Belgium on March 22, 2016. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)
People are evacuated from Brussels Airport, in Zaventem, on March 22, 2016. after at least 13 people have been killed by two explosions in the departure hall of Brussels Airport. / AFP / Belga / VIRGINIE LEFOUR / Belgium OUT (Photo credit should read VIRGINIE LEFOUR/AFP/Getty Images)
Passengers gather, on March 22, 2016 near Brussels airport in Zaventem , following its evacuation after at least 13 people were killed and 35 injured as twin blasts rocked the main terminal of Brussels airport.AFP PHOTO / JOHN THYS / AFP / JOHN THYS (Photo credit should read JOHN THYS/AFP/Getty Images)
Passengers leave with their luggages, on March 22, 2016 near Brussels airport in Zaventem , following its evacuation after at least 13 people were killed and 35 injured as twin blasts rocked the main terminal of Brussels airport.AFP PHOTO / JOHN THYS / AFP / JOHN THYS (Photo credit should read JOHN THYS/AFP/Getty Images)
BRUSSELS, BELGIUM - MARCH 22 : Police officers stand guard around the Zaventem Airport after two explosions went off in Brussels, Belgium on March 22, 2016. (Photo by Dursun Aydemir/Anadolu Agency/Getty Images)
A photo taken on March 22, 2016 shows Brussels Airport, in Zaventem, after two explosions rocked the main hall of the airport. At least 13 people have been killed after two explosions occured in the departure hall of Brussels Airport. Government sources speak of a terrorist attack. The terrorist threat level has been heightened to four across the country. / AFP / BELGA / DIRK WAEM / Belgium OUT (Photo credit should read DIRK WAEM/AFP/Getty Images)
HIDE CAPTION
SHOW CAPTION
of
SEE ALL
BACK TO SLIDE

"MOTHER OF SATAN"

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.

It also loses its potency over time as the chemicals decay.

Used in the 2005 London bombings and the Nov. 13 Paris attacks, and found in a series of foiled bomb attempts in Europe since 2007, TATP appears to be Islamic State's explosive of choice.

However, unlike the smuggled firearms also used in the Paris attacks that killed 130 people, TATP offers no easy trail for European intelligence agents to track because purchasing the ingredients is easily done at any local hardware store or pharmacy and rarely attracts attention.

Making a TATP bomb, although a more lengthy process than the fertilizer-based explosives used by other European militants, is cheap and simple and recipes and videos by chemistry buffs abound on the Internet. It was discovered by a 19th century German chemist and is very powerful, even in small quantities.

All the ingredients - acetone found in cleaning products, hydrogen peroxide found in wood bleach and sulphuric acid used to unblock kitchen pipes - were available at one Brussels hardware store this week for less than 40 euros ($45).

Nails and bolts can be added to increase the bomb's impact and afterwards stuffed into bags and taped into suicide belts.

It goes undetected by airport scanners, leaving authorities to rely on sniffer dogs. Though the bombs can have a strong smell -- the bombers' taxi driver said he smelled chemicals on the ride to the airport -- there were few such dogs in the Brussels' airport check-in area on Tuesday when the men detonated the explosives hidden in holdalls on baggage trolleys, according to several witnesses, including an airport worker.

Aftermath of Attack on Brussels Airport

CHEMISTRY STUDENT

Ehud Keinan, an Israeli scientist who has spent 35 years studying TATP, said that as little as 4 kg could produce the kind of devastation seen in Brussels.

"It is very easy to make, not like a conventional bomb," said Keinan, the dean of chemistry at Technion-Israel Institute of Technology in Haifa. "You don't need to be part of a large organization or need training to do this."

Still, one of the three Brussels suspects, Najim Laachraoui, a 25-year-old Belgian who blew himself up in the airport attack and is suspected of making suicide vests for Paris, had studied engineering at university and excelled in lab work.

Islamic State is also making TATP on an industrial scale in Syria and Iraq, according to a report last month by EU-funded Conflict Armament Research.

The emergence of Kalashnikov assault rifles as a weapon of choice for Islamic State in Europe in the past two years, notably in Paris, has led to EU efforts to crack down on weapons traffickers.

But disrupting TATP supplies is harder.

The European Union in 2014 passed new legislation for all the bloc's 28 countries to restrict the marketing and use of chemicals that could be used to make explosives, and in some cases requires identity checks on those purchasing them.

Within two weeks of the July 2005 London attacks, the British chemical industry and British hardware stores stepped up their reporting of suspicious or large purchases of chemicals.

However, in France, the explosive precursor hydrogen peroxide is sold legally as a way to clean private swimming pool water and no one is considering banning nail varnish remover.

"If you go into any pharmacy in Brussels, you can buy 50 ml of acetone. If you go into a hundred pharmacies, you can get that much more," said Peter Newport, the chief executive of Britain's Chemical Business Association, which sits on the European Commission's expert group on regulating precursors.

"There are so many valid uses by the public of these substances."

($1 = 0.8964 euros)

Read Full Story

Sign up for Breaking News by AOL to get the latest breaking news alerts and updates delivered straight to your inbox.

Subscribe to our other newsletters

Emails may offer personalized content or ads. Learn more. You may unsubscribe any time.