The case of the murdered Russian spy in London

Litvinenko was a former officer in the KGB and an employee of one of its successor organisations, the Federal Security Service (Federalnaya Sluzhba bezopasnosti: FSB). His assassination is the subject of an intense investigation by the Metropolitan Police's new counter-terrorism command headed by Deputy Assistant Commissioner Peter Clarke. The Russian government is officially co-operating with the police inquiry and has strongly denied any direct involvement in Litvinenko's poisoning. Just before Litvinenko's death at around 2100 GMT on 23 November 2006, the Met and the Health Protection Agency announced a significant quantity of the radioactive isotope polonium-210 had been found in his urine.

However, had it not been for the skill of UK scientists, the polonium-210 that was poisoning Litvinenko might never have been detected. Polonium-210 is almost impossible to detect by normal radiological monitoring. It is an alpha radiation source, rather than a gamma or beta source, which most radiation detection equipment is capable of finding.

Retracing events in the public domain in relation to radiation contamination was initiated at the earliest opportunity to ensure public health safety. The Health Protection Agency was fully informed at around 1800 on 23 November, although its director had been spoken to the previous evening. The UK Government response was co-ordinated by the Cabinet Office Briefing Room Committee. The Atomic Weapons Establishment supported the Met and the Health Protection Agency and confirmed the detection of the isotope. In addition, a Defence Science and Technology Laboratory spokesman confirmed it was providing scientific advice and assistance to the police and Health Protection Agency investigation. According to the Met, information about monitoring and decontamination procedures and techniques used in the investigation so far are being withheld for "operational reasons". Alpha scintillation detectors and other devices were cross-calibrated to ensure that monitoring was conducted to the same standard, as not everyone was using the same equipment. The Health Protection Agency suggested a reference contamination level for surface monitoring of 10 becquerels per square centimetre (BQ cm2).

By 13 December 2006, 26 venues had been monitored and varying degrees of polonium-210 contamination have been found at approximately 12 locations in London. Particularly high concentrations of polonium-210 contamination were found at the Pine Bar at the Millennium Hotel where Litvinenko allegedly met ex-KGB bodyguards Dimitry Kovtun and Andrei Lugovoi on 1 November and at the Piccadilly branch of the Itsu sushi restaurant where he met Italian security expert Mario Scaramella. There are no health concerns in key public areas.

While all tests on Itsu staff were negative, nine Millennium Hotel workers and a staff member from the Sheraton Hotel in Park Lane have subsequently tested positive. The Health Protection Agency also encouraged overseas guests at the hotel who went to the Pine Bar to contact the NHS. Health Protection Agency scientific media spokesman Dr Michael Clark says it took a week to gather all the samples needed from the hotel's employees. Counselling was also an important part of the Agency's response.

The Barnet and University College hospitals where Litvinenko was treated were found to have no contamination that would pose a risk to public health. There was also no risk found at the Emirates Stadium where a contact of Litvinenko, Vyacheslav Sokolenko, attended a football match, nor on board three British Airways aircraft.

Radiological first

Although the precise motivation of the people involved in killing Litvinenko remains unclear, the use of a radiological weapon is a first for the UK. Moreover, it has some of the characteristics of a terrorist attack and may also have been intended to intimidate opponents of the Russian government.

Between the issuing of Health Protection Agency advice on 25 November and 18 December 2006, the NHS Direct helpline received 3,806 calls about possible radiation poisoning. A total of 29 people (27 callers to NHS Direct along with two people from other sources) were referred for radiological exposure assessment. At the time of writing, 21 of these people had provided urine samples that were clear and six samples were still being tested.

Testing for polonium-210 is not straightforward. No external monitoring equipment can detect whether someone is contaminated. The Health Protection Agency's laboratory at Chilton uses a method that involves a 24-hour urine sample test. This time is needed to chemically process and separate polonium-210 from the rest of the urine sample and allow for a sufficient number of radioactive decays to take place. Twelve hours is long enough to measure a minimum detectable level of 20 mega BQ for a 24 hour sample. Exposure to polonium-210 is not a risk to human health as long as it remains outside the body. However, irreparable tissue damage occurs once it enters the body through eating or drinking contaminated food, breathing contaminated air or through a wound. There is no antidote.

The biological half-life of polonium-210 inside a person, the time it takes the isotope's levels to drop by half through natural excretion, is approximately 50 days. Alpha particles can travel a few centimetres, can only penetrate to approximately 60 micrometres and are stopped by a sheet of paper or the dead layer of outer skin on our bodies.

An autopsy was conducted on Litvinenko on 1 December at the Royal London hospital. On the basis of advice from Health Protection Agency experts, special measures were followed during the autopsy to ensure medical staff safety, including monitoring radiation levels. Further procedural details of how the autopsy was carried out will not be released until the inquest is resumed. The autopsy report will also remain confidential unless criminal proceedings are brought.

European assistance

The Health Protection Agency has also been in contact with a number of European laboratories including the Forschungszentrum in Germany, the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) in France, the Belgian Nuclear Research Centre (SCK-CEN) and the International Atomic Energy Agency's (IAEA) analytical laboratory in Seibsdorf, Austria.

According to the International Atomic Energy Agency (IAEA), polonium-210 has a half-life of 138 days due to radioactive decay and eventually becomes stable lead polonium-206 by emitting alpha particles and, once every 100,000 decays, one gamma ray. Using high neutron fluxes found in nuclear reactors, around only 100 grams of polonium-210 are produced each year.

Therefore, spectral analysis of the isotope that killed Litvinenko will help identify where it was made.

The IAEA has an illicit trafficking database that logs incidents where polonium-210 sources contained in static eliminators and air ionisers have been stolen, lost or disposed of. Extracting polonium-210 would require chemical treatment in a laboratory. The most likely way of producing the isotope would be to bombard the element bismuth in a reactor with neutron particles in order to produce bismuth-210. This then decays to polonium-210 and a radioactive thallium-206. The early assumption that Litvinenko had been poisoned with thallium may indicate the use of reactor-produced polonium-210. In the whole affair, the effectiveness of the UK Government's chemical, biological, radiological and nuclear (CBRN) response has been critical.

The Department for Environment, Food and Rural Affairs (DEFRA) issued guidance covering a generic CBRN response in 2004 and local authorities play a leading role in this in co-operation with other public and private sector organisations. In the Litvinenko poisoning, this was Westminster City Council, the Government lead department was the Home Office which, in addition to the Met and the Health Protection Agency, was supported with expert scientific advice that council could also draw on.

Without decontamination, polonium-210 takes five years to completely decay so Westminster City Council will develop a recovery plan under DEFRA's guidance. It will organise and manage the decontamination process and restore contaminated environments to their normal use, and manage the health and safety risk of workers undertaking decontamination and the processing of hazardous wastes.

The Environment Agency and the police also have roles and responsibilities that they are currently conducting. Issues such as who is paying for the decontamination are not yet in the public domain. A Health Protection Agency assessment is expected to be the final tick in the box.

Alexander Litvinenko's poisoning has many ripple effects that have not yet been felt. But a Met Police source told RUSI that the incident is useful as a real-life exercise and, when dissected, generate lessons that may prove useful should a more severe CBRN incident take place.