Chemical attack test for London Underground

[damian_steele]

The government is to carry out tests to see how toxic substances would spread if used by terrorists on the Tube.

A harmless chemical - sulphur hexafluoride - will be used to monitor airflows at north-west London's St John's Wood London Underground station.

Services will run as normal on the two Sundays chosen for the tests, 25 March and 1 April 2007.

Scientists from the Ministry of Defence will be in charge of the tests, which they say pose no safety risks.

It follows trials on both the Tube and at mainline train stations of passenger screening, with people volunteering to take part.

The first trial of passenger screening technology took place at Paddington station in west London in January 2006 and was followed by further trials at Canary Wharf and Greenford Tube stations.

Trials also took place last August to test the practicalities of deploying portable vehicle access control barriers at major entry points at Waterloo and Victoria stations in London.

Announcing the St John's Wood tests, Transport Secretary Douglas Alexander said: "The purpose of the study is to gather data within a genuine rail environment.

"It is not a reaction to any threat increase or a measure to enhance security at this or any other station.

"All the data and feedback gained will merely help to inform future decisions."

Mr Alexander said the public understood providing airport-style security on open systems such as the rail and Tube networks was unworkable and that no single security measure was either foolproof or capable of mitigating every threat.

http://news.bbc.co.uk/2/hi/uk_news/e...on/6454075.stm

I wonder how many people will see the test and believe it is a real attack?

Or will the public be as blind as usual and not even notice anything at all?

[kengillam]

This is the Gas
Sulfur hexafluoride can affect the sound of a person's voice if it is inhaled in small quantities. When SF6 is inhaled, the pitch of a person's voice decreases dramatically.

Although inhaling SF6 can be a novel amusement, the practice can be dangerous because, like all gases other than oxygen, the SF6 displaces the oxygen needed for breathing (a phenomenon known as asphyxiation). A myth exists that SF6 is too heavy for the lungs to expel unassisted, and that after inhaling SF6, it is necessary to bend over completely at the waist to allow the excess gas to "spill" out of the body. In fact, the lungs mix gases very effectively and rapidly, such that SF6 would be purged from the lungs within a breath or two.[4] In general, dense, odourless gases in confined areas present the hazard of suffocation.

So much for safe for the public then !!

[damian_steele]

The Environment Agency's own website says:

Sulphur hexafluoride is a man-made chemical, an unreactive, non-toxic heavy gas with no colour and no smell. Sulphur hexafluoride is a "greenhouse gas" - releasing it to the atmosphere contributes to global warming.

Nice to know our chaps have thought about the environmental consequences, too.