Publication: Journal of Environmental Health
Date published:
Language: English
PMID: 23855
ISSN: 00220892
Journal code: PENV


On November 23, 2006, shortly before former Russian military intelligence officer Alexander Litvinenko died in a London hospital, authorities determined he suffered from acute radiation syndrome after ingestion of Polonium-210 (210Po). The Metropolitan Police immediately began a criminal investigation.

As a rule, public health authorities do not actively participate in criminal investigations, let alone any that involve a targeted attack resulting in a single homicide. But the unique nature of the weapon used to kill Mr. Litvinenko put many people at risk - people who had nothing to do with the crime. 110Po is very deadly, and it very easily becomes airborne (Roessler, 2007). If ^sup 210^Po is released into the environment, the contamination quickly spreads to surrounding areas. The body takes in ^sup 210^Po by ingestion, inhalation, or absorption though skin; thus ^sup 210^Po can find its way into virtually all body excreta, including perspiration (Harrison, Leggett, Lloyd, Phipps, & Scott, 2007). People internally contaminated with ^sup 210^Po can therefore spread it to anything they or their excreta contact.

In fact, a London Telegraph article reported that the authorities declared Mr. Litvinenko's body a major environmental hazard and held it for two weeks. The body was only released in a sealed casket provided by the United Kingdom Health Protection Agency (HPA). The family was told that if they were to cremate Mr. Litvinenko's remains, they would have to wait for 28 years, until all the radioactivity in the body decayed to safe levels - nearly 80 half-lives of ^sup 210^Po (Volodarsky 2009).

In the days following Mr. Litvinenko 's death, the Metropolitan Police used technical experts to track the locations visited by "persons of interest" in the case. The alleged perpetrators stayed in three different hotels and, during their apparent rehearsals of the murder, carried containers of 210Po to several different public places. Many of these locations showed detectable traces of ^sup 210^Po contamination. Investigators initially designated the locations as crime scenes and scoured them for evidence. But more locations than just the crime scenes showed evidence of contamination. Public areas such as hallways, restrooms, and gathering places of various types were also contaminated with ^sup 210^Po.

After the Metropolitan Police investigators completed their forensic examination of a site, they released it to HPA for further evaluation (Bailey et al., 2010). HPA, in turn, assumed responsibility for environmental monitoring of all public locations where contamination was positively identified and for taking actions to keep that contamination from spreading (e.g., closing restrooms, painting walls, removing furniture). HPA was also charged with identifying members of the public who had inadvertently come in contact with ^sup 210^Po. Eventually, authorities found ^sup 210^Po in

* the two hospitals where Mr. Litvinenko was treated,

* various business offices in London,

* coffee bars and nightclubs,

* a football (soccer) stadium,

* airplanes,

* automobiles, and

* three hotels.

Thus what began as a targeted, ^sup 210^Po poisoning attack mushroomed into a radiological dispersal incident. A "dirty" bomb is the most commonly feared form of radiological dispersion, where detonation of a conventional explosive device releases radioactive materials into the environment. Here, ^sup 210^Po dispersed into many areas of London became, in effect, a nonexplosive "dirty" bomb.


As noted, one of HPAs major responsibilities was to identify persons contaminated with ^sup 210^Po. To do so they interviewed many people who worked in or visited locations of interest, such as hospital workers who attended Mr. Litvinenko. They also released carefully worded public statements designed to educate, to alleviate concerns, and to alert persons believed at increased risk for contamination. People HPA identified as at increased risk were invited to provide the authorities with a 24-hour urine sample to estimate their total ^sup 210^Po body burden. HPA also provided urine testing to concerned citizens who requested it, even those considered low risk. Through August 2007, HPA provided such biomonitoring (or bioassays) to more than 700 persons (Bailey et al., 2010).

Usually, the health risks associated with environmental exposures to radioactivity are primarily stochastic in nature, such as cancer. As shown in Table 1, however, ^sup 210^Po is so toxic that only small amounts of this material can cause death (Scott, 2007). A quantity of ^sup 210^Po no larger than the period at the end of this sentence would be sufficient to kill a human. Although anyone incidentally exposed to ^sup 210^Po in the environment would probably not receive a lethal dose, in the first days and weeks of the HPA investigation authorities could not rule out that possibility.

Inevitably, some who were potentially contaminated with ^sup 210^Po were foreign nationals. The HPA identified over 600 persons from 52 countries outside the UK as potentially at risk of ^sup 210^Po contamination (Bailey et al., 2010). Of these identified persons, about 25% were U.S. citizens. The Centers for Disease Control and Prevention (CDC) became the main point of contact between HPA and these citizens. Working directly with the HPA and through the U.S. Department of State, CDC advised individual citizens and provided health care professionals and state and local public health officials with guidance on how to respond to this incident.

In March 2007, HPA staff hosted a oneday conference in London. Oral and poster presentations explained their response to Mr. Litvinenko's death, including lessons learned (Lightfoot, 2007). During the course of working with both HPA and U.S. officials in response to this incident, CDC staff identified a number of teachable opportunities useful for helping public health officials prepare for a radiological incident in the U.S. This article summarizes those opportunities.

Lessons Identified

The sections below are summaries of eight major lessons CDC staff have identified as a result of our domestic response to this incident. Oftentimes, such items are presented as "lessons learned" or issues identified. We have adopted the approach used by our UK colleagues. Until actions are actually implemented to correct identified issues, no lesson has really been learned.

1. Identification of the Poison

As noted above, until just hours before death ^sup 210^Po had not been identified as the poison that killed Mr. Litvinenko. At some point during his medical care, hospital personnel reportedly surveyed Mr. Litvinenko with a standard Geiger-Mueller counter. Finding no evidence of contamination, they ruled out radiation poisoning as a cause of his unexplained illness (Perkins, 2007). But ^sup 210^Po decays primarily by release of alpha particles, and a standard Geiger-Mueller counter cannot measure alpha particles inside a person. Only a well-equipped and well-trained radiation spectroscopy laboratory can identify a person internally contaminated with such a radio nuclide.

Here, however, delayed identification of the radionuclide did not significantly affect Mr. Litvinenko's prognosis. Given 210Po1S lethality, even if the treating physician had known immediately what Mr. Litvinenko had ingested, death was a virtual certainty. Yet if Mr. Litvinenko had been exposed to some other radionuclide, death might not have occurred. The point is that radionuclide poisoning is a rare incident, and authorities eventually did identify the poison. But whenever public health practitioners are faced with an illness without an obvious diagnosis, they should keep radiation poisoning in mind as a possible cause.

2. Public Communication

Mr. Litvinenko died on a Thursday. By Friday morning HPA had already begun the process of providing key public health messages. HPA leadership appeared on all major national television outlets, and staff posted public information on the agency's Web site (Lewis, 2007). One of HPAs stated objectives was to reassure the public that, in general, people were at very low risk of adverse health effects.

One obstacle HPA faced in reaching its objectives was the ongoing criminal investigation. HPA was prevented from releasing pertinent details about the case that would have allowed persons to make informed decisions about their own risk level. That said, researchers looking at the effectiveness of HPAs messages determined that the public understood the trigger incident was criminal in nature, not terrorist. And people generally trusted the opinion of public health officials who told them that they were at low risk for contamination. Yet those same members of the public who participated in the communications effectiveness research study made clear that they preferred solid information to reassurances (Rubin et al., 2007).

People who did undergo urine testing had difficulty understanding the significance and long-term implications of the test results as reported. ^sup 210^Po is a naturally occurring radionuclide, and all people have some level of ^sup 210^Po in their urine. In general, smokers have higher levels of ^sup 210^Po in their urine than do nonsmokers (Santos, Gouvea, & Dutra, 1994). Although population reference ranges for ^sup 210^Po levels in urine are not available, HPA surveyed the results of the urine measurements for each person tested, and categorized those results as

* measured levels are of no health concern (estimated doses <1 mSv [milliSievert]);

* measured levels represent some level of additional exposure but they do not represent a health concern (estimated doses >1 mSv-<6 mSv); or

* measured levels represent some level of concern for increased risk of developing cancer sometime in the future (estimated doses >6mSv).

When reporting results for U.S. citizens, CDC used the same language.

Table 2 contains monitoring results reported for UK residents. Over 92% of the results were in the "of no concern" category. People interviewed in the postincident communication study (Rubin et al., 2007) reported they found this reporting method "unhelpfully vague." These respondents wanted their actual numerical results and information on how to interpret them, especially insofar as long-term health effects were concerned (Rubin et al., 2007). These reactions illustrate the challenge of providing appropriate health information to the public when radiation or radioactive materials are involved. Reports from Canada (Cornett et al., 2009) and Israel (Brosh-Nissimov, Havkin, Davidovitch, Poles, & Shapira, 2008) have helped to expand the international discussion of the public communication challenges in an incident such as Mr. Litvinenko's murder.

One of CDC's first efforts to assess U.S. citizens for potential ^sup 210^Po exposure involved individual contact. In most cases, CDC contacted citizens by phone, e-mail, or letter. In others, CDC contacted state or local health departments and provided lists of citizens to contact within their jurisdictions. Additional resources such as phone interview scripts were provided to the state and local health departments for initial interviews and for individual follow-up.

CDC also prepared and provided educational information about the incident and about laboratory testing to citizens, to their private physicians, and to state and local health departments. Communications and educational information were posted on the CDC Web site, disseminated through CDC's Health Alert Network and EPI-X secure network notification systems, and provided directly to citizens and their physicians.

Communications challenges with state and local health agencies primarily involved limited awareness or understanding. A particular problem was a lack of knowledge about the state and local health department responsibilities during a radioactive materials incident. In some cases, state and local health department officials could not locate their own state's radiation control program contact. This occurred even in those states where the government's organizational structure placed public health departments and radiation control program offices in a common location. CDC provided public health departments with contact information for their radiation control program, if requested. But CDC cannot be certain that other health departments made the correct connections to their local radiation control offices.

Some U.S. citizens or their physicians requested urine testing. CDC either offered to collect the specimens and have them analyzed or offered referrals to accredited private laboratories. CDC laboratory personnel also provided collection materials and information regarding sample collection, processing, shipping, and offered assistance in interpreting the laboratory results.

Thirty-one persons requested to have their laboratory urine results interpreted by CDC. Using these laboratory results, CDC health physics staff performed dose assessments. These individual dose assessments were based on internationally recognized and accepted methods similar to the dose assessments HPA used when it assessed UK citizens for potential exposure (Bailey et al., 2010). CDC communicated the interpreted results by direct mail. All dose estimates for U.S. citizens tested were <1 mSv.

3. International Collaboration

U.S. citizens in the UK in November 2007 included those on business travel and tourists on a possible once-in-a-lifetime visit to London. But on any given day, every major city in the world hosts international visitors. Public health officials must be prepared to collaborate with the international public health community in radiological incidents that occur within their jurisdictions.

The HPA approached this challenge via two routes. First, they worked through the UK Foreign and Commonwealth Office to provide the embassies the names of all identified persons at risk who had been potentially contaminated with radioactive material. Second, HPA took advantage of preexisting contacts with health officials in other nations and contacted them directly (Bailey et al., 2010). CDC became involved through both mechanisms. Rules finalized after this incident now require international notification of public health incidents involving radiation and radioactive materials (World Health Organization, 2005). Public health officials must be prepared to implement such requirements.

4. Identification of Potentially Contaminated Persons

HPA immediately faced the question of how to identify people potentially contaminated with 210Po. This question applied, of course, to both UK residents and to international visitors. For example, officials used credit card receipts to identify some people who had visited contaminated bars and restaurants. But for one person to pay the bill for everyone at a table is not uncommon. In business settings, especially, a single credit card receipt may represent several persons. Only a conversation with the credit card holder will reveal that information, and that assumes the credit card holder will share it with an interviewer. Moreover, some people pay their bar or restaurant bills with cash. Thus some potentially exposed persons associated with this incident will likely remain unidentified.

HPA also prepared carefully crafted public messages and established telephone lines to identify potentially contaminated people whom HPA could not readily identify by name. This procedure, of course, resulted in a number of calls from people who were highly unlikely to have been contaminated but who were nonetheless concerned about radiation exposure. Operators receiving such calls must be prepared to triage effectively and compassionately.

CDC likewise experienced challenges in identifying U.S. citizens potentially exposed to ^sup 210^Po while visiting London. Initial lists of identified citizens obtained from the HPA were expanded to include others subsequently identified through telephone interviews. For example, additional persons were added based on those who may have paid for a number of persons on a single credit card at a location of interest or of known contamination. Others were added based on hotel booking in one name reserved for another person in the same business organization.

Any major public health emergency will have to deal with the challenge of identifying potentially affected people. But incidents involving radiation exposure are rare, and during such incidents people have been known to be more concerned about radiation than about many other contaminates or infectious agents. That could mean a flood of telephone and Internet inquires, many of which could lead to identification of still more potentially contaminated persons. The public health community should carefully preplan to deal with identification issues associated with such an incident.

5. Contamination Control

The "silent source" is another terrorist radiation-exposure tactic. It involves the placement of radioactive material in a location where people are covertly exposed to radiation, but without contamination from the radioactive material itself. Such an attack is often premised on a sufficient time lag before discovery to expose and therefore harm a maximum number of people. Some press reports have suggested the occurrence of at least one silent source incident in Russia (Specter, 1995).

The London ^sup 210^Po poisoning was a contamination incident, not a silent source incident. Still, one common characteristic was nondiscovery of the poisoning effects until many days after initiation of the contamination process. In London, before authorities could control the 210Po contamination, it had already fanned out to expose large numbers of people.

People in London stated that they understood the ^sup 210^Po poisoning was aimed at one person and that they were not targets. If, however, terrorists were to use a similar incident to target a larger group of people, how quickly that incident was discovered could affect the public -health messaging process. For example, UK officials were very concerned about reassuring the public that the risk of harm to them was very low. A terrorist incident would likely make that task much more difficult, and the economic impact on a major city from such an incident could be very high.

6. Medical Management

The U.S. Department of Health and Human Services (HHS), including CDC, recommends that during a radiological incident, medical management of life-threatening injuries should nearly always take precedence over contamination concerns (HHS, 2010). Numerous national and international radiation protection organizations support this position.

But some first responders and first receivers have traditionally rejected it. As part of allhazards training, health care providers have been taught not to transport or treat any person contaminated with a biological, chemical, or radioactive agent until after decontamination. Only after sustaining a penetrating injury from a highly radioactive piece of shrapnel should a victim receive decontamination before delivery of other life-saving care. And the shrapnel is promptly removed primarily to prevent high-dose radiation exposure to first responders and medical personnel (Smith, Ansari, & Harper, 2005).

Note in this regard that in the Litvinenko case, prehospital health care providers, the medical staff, the housekeeping staff, and others who tended him from the time he became ill until almost his dying moment did not know that he and all of his body fluids, including excreta, were highly radioactive. Hospital staff assumed they were dealing with an unknown infectious or communicable disease. They used the standard "universal precautions" to protect themselves. HPA was obviously very concerned about the potential for internal contamination of the caretakers. In Table 2 HPA has reported the 210Po bioassay results for 78 health care workers (Bailey et al., 2010). HPA identified one worker who may have been exposed, but the level was below any health concern. Results for the other 77 health care workers all showed levels "of no concern."

Although this was most certainly not a well-controlled, statistically defensible, epidemiological study, the "no level of concern" results for 77 workers adds credence to CDC's position that immediate life threatening care be given before decontamination. The public health and medical community has a responsibility to protect and treat potential victims of terrorist activities involving radioactive materials and to help the medical and emergency response personnel understand how to protect themselves, their staff, and their facilities and equipment while administering life-saving aid.

7. Laboratory Capacity

The HPA bioassay laboratory used a 24-hour collection of urine to assess people for ^sup 210^Po contamination. Although HPA radioanalytical chemists knew how to do this, they lacked the capacity to perform rapidly a significant number of such tests, especially in a very short period of time. HPA thus had to establish a validated procedure they could use for this incident and then reach out to every UK laboratory they could identify who could also do the analysis using the same or equivalent validated procedure. They also established quality control procedures using performance testing materials to insure that results from all involved laboratories were accurate, precise, and within acceptable limits. It was a considerable challenge for the UK to have enough bioassay laboratory capacity to perform the 752 analyses that they conducted (Table 2) (Bailey et al., 2010).

CDC staff faced a similar problem as their British colleagues: a shortage of accredited laboratories capable of reliable 210Po assays on clinical samples. An aggressive search by CDC identified any one of a number of state and local government laboratories capable of measuring radionuclides in environmental media (such as water and soil). None, however, were clinical laboratory improvement amendments (CLIA)-certified to assay for 210Po in urine. CDC did locate one CLIAcertified commercial laboratory prepared to perform these measurements; one additional laboratory attained CLIA certification in late December 2006. In total, CDC obtained the 210Po urinary assay results for 31 U.S. citizens. All bioassay results for U.S. citizens were "levels of no health concern."

Another difficulty CDC laced (although not in the UK) was the inability to account for all samples potentially submitted for analysis. SomeU.S. citizens may have submitted samples privately through their personal physicians. CDC has no assurance that it has a comprehensive list of results from all U.S. citizen samples tested. The laboratories performing the assays proved reluctant to share results, citing concern over potential violations of the Health Insurance Portability and Accountability Act of 1996 privacy rule. Inability to obtain a full-line list of potential victims to an incident would surely hamper any efforts at tracking victims of potential incidents.

Fortunately, the number of potentially contaminated U.S. citizens was sufficiently small that one or two laboratories could handle it. The Litvinenko murder, however, exposed our difficulty in monitoring the population rapidly should such an incident ever occur on U.S. soil. We currently lack sufficient laboratory capacity to handle such an incident.

8. Sustaining the Response

One of the major lessons HPA staff identified was the difficulty they faced in sustaining a prolonged response effort (Lightfoot, 2007). Even after mobilizing a significant portion of their organization, the staff worked extended hours, seven days a week, for almost the entire month of December. At a debriefing held in March 2007, HPA reported staff was still involved in the 210Po public health response, albeit at a much lower level of activity than earlier. HPA also noted that many public health officials called upon to assist in the response effort had no formal training in radiation.

In the U.S., response sustainability was not a major limitation. Nevertheless, had a similar incident occurred here, undoubtedly it would have tested the limits of federal, state, and local public health resources.

Although some radiation subject-matter expertise is available throughout the U.S., finding it can be a little difficult. Depending on the locality, radiation control programs and staff may be assigned to a variety of places within the government structure. In some states and cities, for example, radiation control programs are colocated within the public health department. In other states and cities, they are not. During this particular response, CDC was faced with the challenge of putting public health officials and members of the public in contact with their state or local radiation experts.

Because radiation control programs are not located consistently within state and local government structure, it is imperative that public health officials and their radiation control counterparts meet, develop response plans, and know how to reach each other well in advance of an event involving radiation or radioactive materials.


In the response to any type of incident in which a number of people have been or potentially could have been exposed to radiation or contaminated with radioactive material, the U.S. public health community will play a significant role. The circumstances of Mr. Litvinenko's death have identified a number of useful lessons for planning responses to similar incidents. Public health and medical authorities must learn to

* consider and possibly test for radionuclide poisoning when faced with an illness that does not have an obvious diagnosis,

* prepare appropriate health information for the public when radiation or radioactive materials are involved,

* be prepared to implement international notification requirements for incidents involving radiation or radioactive materials,

* engage in some preplanning to deal with issues related to identifying persons potentially affected by a radiological incident,

* consider how radionuclide contamination incidents can best be identified and controlled,

* help medical emergency response personnel understand their level of personal risk when caring for victims of radionuclide contamination,

* develop the laboratory capacity to allow the U.S. to respond rapidly and efficiently to a major radionuclide contamination incident, and

* engage in coordinated preplanning efforts with radiation control counterparts.

We need collectively to learn these lessons well and apply them appropriately as we plan and prepare for public health responses to radiation emergencies. Then, should a Litvinenko-like incident occur in the U.S., we can provide immediate and effective assis tance to people.


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Author affiliation:

Charles W. Miller, PhD

Robert C. Whitcomb, PhD, CHP

Armin Ansari, PhD1CHP

Carol McCurley, MS

Radiation Studies Branch, Division

of Environmental Hazards and

Health Effects, National Center for

Environmental Health, Centers for

Disease Control and Prevention

Jeffrey B. Nemhauser, MD

Office of Public Health Preparedness

and Response, Centers for Disease

Control and Prevention

Robert Jones, PhD

Inorganic and Radiation Analytical

Toxicology Branch, Division of

Laboratory Sciences, National Center

for Environmental Health, Centers for

Disease Control and Prevention

Author affiliation:

Corresponding Auihor: Charles W. Miller, Chief, Radiation Studies Branch, Division of Environmental Hazards and Health Effects, National Center for Environmental Health, Centers for Disease Control and Prevention, MS:F58, 4770 Buford Highway NE, Atlanta, GA 30341-3717. E-mail:

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