Poison gas attack foiled in Britain

By KIM SENGUPTA

A planned poison gas attack, with the London underground system as a likely target, has been foiled by the security agencies, it was claimed today.

The plot, by British based supporters of al Qaeda, allegedly involved detonating a combined chemical and explosive "dirty bomb", producing fumes which can choke victims in a confined place.

The conspiracy was uncovered after British and United States intelligence intercepted telephone calls within this country, as well as calls to alleged senior members of the group in Pakistan.

As well as tube trains, passenger terminals at London's Gatwick and Heathrow airports are believed to have been in the list of targets. However, it is believed the plot was exposed before the alleged terror cells had reached the position to carry out an attack.

Security sources said yesterday that the attack involved the use of a chemical called osmium tetroxide to set off a blast.

The substance turns from solid to gas in confined space and is highly corrosive to eyes, skin tissue and lungs, producing a symptom called "dry land drowning."
It is believed that a fertiliser-based explosive would have been part of the package.

The telephone calls between the alleged plotters were intercepted by GCHQ (the Government Communications Headquarters) in Cheltenham, Gloucestershire, and the US National Security Agency.

At least two members of the group have been under surveillance because of their supposed links to al Qaeda affiliates in Pakistan. They are believed to have been tracked for over six weeks.

Al Qaeda leaders have been warning of a chemical attack since the 1999 bombings of the World Trade Centre in New York, and handbooks have been produced on how to manufacture "dirty bombs".

However, so far, the organisation and its affiliates had only carried out attacks with conventional explosives, and some experts pointed out yesterday that osmium tetroxide, which has a legitimate scientific use, did not fit the usual profile of a typical chemical warfare agent.

Handling the chemical would be potentially dangerous for would be bombmakers, and it is highly expensive --- costing between £ 100 and £ 130 a gramme.

Professor Alastair Hay, professor of environmental toxicology at Leeds University, said the substance, known as a ' rare catalyst', a chemical that speeds experiments, could be used to speed up an explosion.

But, he added " It would not be in the same category as some radioactive substance which would continue to emit radiation and cause a problem in terms of clean-up. This would be something present, like a heavy metal lead, in the environment. I don't think it would be a major hazard and clean-up would not be a major problem."

Dr Steve Simpson, a senior lecturer in chemistry at the University of Salford, who works with the substance, said " If you get the vapour in your eyes, even a small amount, it can turn them brown or black and you could be permanently blinded. It is so volatile that one could be in appreciable danger just opening a bottle.

" If one had 10 grammes and opened it up in a normal-sized room, within a couple of minutes it would cause peoples' eyes to stream. Some people might feel a bit tight in the chest. It would cause massive panic. But it is one of the most unlikely things to put in a bomb. You wouldn't get a lot of osmium for more than £30,000....it would be incredibly difficult to put in a bomb."

Dave Siegrist, of the Potomac Institute of Policy Studies, near Washington DC, said "It is a nasty piece of work. It leads to an asthma-style death, something called dry-land drowning."

Quantities of osmium tetroxide is present in many university laboratories in the country, and it is available for purchase through the internet.

- INDEPENDENT