CHEMICAL WARFARE AGENTS: DETECTION (Hansard, 26 July 1994)

§ Lord Henley

Responsibility for this matter has been delegated to the Director General and Chief Executive of the Chemical and Biological Defence Establishment, who has been asked to arrange for a reply to be given.

Letter to the Countess of Mar from the Director General of the Chemical and Biological Defence Establishment, Dr. Graham Pearson.

1. Your Parliamentary Question asking Her Majesty's Government whether they are aware that on 1 July 1994 80WA personnel at the Chemical and Biological Defence Establishment, Porton Down, acknowledged that chemical detectors (NAIAD and CAM) could be activated by substances other than the toxic chemicals they were designed to detect, and by what means military personnel involved in Operation GRANBY were expected to know when they should use their personnel protective equipment has been passed to me to answer as Chief Executive of the Chemical and Biological Defence Establishment at Porton Down.

2 The role of the Chemical and Biological Defence Establishment is to carry out work to ensure that the British Armed Forces have the most effective protective measures possible against the threat that chemical or biological weapons may be used against them.

3 The occasion on 1st July 1994 was the third visit by the Harvard Sussex Programme on CB Armament and Arms Limitations and the Working Party on CBW to the Chemical and Biological Defence Establishment for visits to laboratories and to have wide ranging discussions with myself and members of my staff. As always, these visits and discussions have been arranged to take place under Chatham House rules. They are much appreciated by the participants as they enable a much better understanding of chemical and biological defence to be obtained.

4. The principal route by which chemical warfare agents attack the body is through the respiratory tract although some agents such as mustard and some nerve agents are percutaneously active. The aim in designing an effective detector is to obtain sufficient specificity without reducing sensitivity to a level in which personnel would be exposed to a harmful concentration prior to the detector responding.

5. The British chemical agent detectors such as NAIAD and CAM are designed to be highly specific whilst having a sufficient sensitivity to ensure that those utilising such detectors receive a warning from the detector before they inhale a harmful concentration of chemical warfare agent. Although they, like all other chemical warfare agent detectors, can respond to substances other than chemical warfare agents, it is important to recognise that these other substances are very unlikely to be present on the battlefield in concentrations sufficient to produce an alarm. In practice, the use of more than one type of detector reduces the chance of possible false alarms whilst retaining an undiminished capability for the detection of chemical warfare agents.

6. Consequently, British Service personnel serving in Operation GRANBY donned their personal protective equipment when they were judged to be under a possible chemical warfare attack. This is known as the Immediate Action Drill and is designed to ensure that Service personnel are protected should they be subjected to an attack in which chemical weapons may be used. Likewise, if a chemical detector such as NAIAD or CAM alarms, then full protective equipment is donned. The information relating to the possible attack is then passed to the next high level of command at which judgement will be made as to whether chemical warfare agents have indeed been used in such an attack. Such a judgement would take into account whether other 81WA techniques for detection and monitoring of chemical warfare agent have indicated the presence of a chemical warfare agent or not. The equipment provided to the British Armed Forces to detect and monitor chemical warfare agents is highly effective and is second to none.