Investigators revealed that the explosives used by the Brussels suicide bombers on March 22 contained ammonium nitrate and TATP, also known as triacetone triperoxide. News reports said the explosives were estimated at 44 pounds each and were packed with nails and screws. At least 31 people were killed and nearly 300 injured in the explosions, two of which occurred at the Brussels international airport departure terminal shortly before 8:00 a.m., and a third later that morning at a subway station about seven miles away.
The Belgian prosecutor’s office reported that authorities found more than 33 pounds of TATP during a March 23 raid on a residence linked to the suspects, as well as nearly 40 gallons of acetone and eight gallons of hydrogen peroxide, the materials used in producing TATP. Also found at the residence were nails and screws, and an Islamic State flag. Investigators said two undetonated bombs constructed with 20-40 pounds of TATP, ammonium nitrate, and a mix of metal bolts and nails were found in suitcases at the airport. A suicide belt was also recovered at the airport, and two more suitcases with bombs were confiscated during the sweep of the residence.
Experts cited by news media said TATP has become a common choice for terrorists because the chemical components are much easier to purchase than bulk quantities of ammonium nitrate. TATP is a peroxide-based rather than nitrogen-based explosive, which makes it harder to detect. TATP can also be used as a booster charge to trigger an ammonium nitrate detonation. TATP is also believed to have been used in the terrorist attacks in Paris in November.