Bombs were peroxide-based

2005-09-20 18:35

London - The bombs used in the July 7 attacks on the London transit system were peroxide-based, carried by the bombers in coolers the morning they struck, police said on Tuesday.

Investigators said they found two unexploded bombs in a car the suspected attackers left at a train station north of the capital. Those devices were also made of peroxide and were surrounded by nails, police said.

Police did not immediately specify how they knew the bombs that exploded aboard three London subways and a bus were made from peroxide.

There had been speculation for weeks that the explosives were peroxide-based, but police had not confirmed it publicly.

Peroxide-based explosives degrade at room temperature and must be kept cool until used.

Bombs well made

Peter Clarke, head of London's Metropolitan Police anti-terrorist branch, said the bombs had been "effectively made" and whoever made them had "done some good research and had been well trained".

Clarke said forensic officer had found traces of HMTP, a type of peroxide explosive, in a Nissan Micra the suspected bombers left at Luton train station, north of London.

Andy Oppenheimer, an explosives expert with Jane's Information Group, said HMTP was one of a group of explosives made from common, easily available items such as hydrogen peroxide, which is used as hair bleach.

"It's another kind of explosive that could be made in somebody's premises," he said. "There are quite a lot of these peroxide-based explosives and they are quite popular with terrorist groups and in crime because they are relatively easy to obtain."

However, he added, "they are not easy to put together - they can be very unstable. People often blow themselves up in the process of making it."

He said peroxide-based bombs could be quite powerful, although not nearly as strong as plastic explosives.

- AP