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Civil and military force sent to deal with the aftermath of the Chernobyl disaster
A group of Liquidators gathered at the Museum of Slavutych on the 32nd anniversary of the Chernobyl disaster, 2018
Soviet military badge (left) and medal awarded to liquidators.
The central detail of the Liquidators' medal, with traces of alpha (α) and beta (β) particles and gamma (γ) rays over drop of blood.
The Chernobyl liquidators were the civil and military personnel who were called upon to deal with consequences of the 1986 Chernobyl nuclear disaster in the Soviet Union on the site of the event. The liquidators are widely credited with limiting both the immediate and long-term damage from the disaster.
Surviving liquidators are qualified for significant social benefits due to their veteran status. Many liquidators were praised as heroes by the Soviet government and the press, while some struggled for years to have their participation officially recognized.
The colloquial term "liquidator" (Ukrainian: ліквідатор, Belarusian: ліквідатар, Russian: ликвида́тор, likvidator) originates from the Soviet official definition "участник ликвидации последствий аварии на Чернобыльской АЭС" (uchastnik likvidatsyiposledstviy avarii na Tchernobylskoi AES, literally "participant in liquidation of the Chernobyl NPP accident consequences") which was widely used to describe the liquidators' activities regarding their employment, healthcare and retirement. This exact phrase is engraved on the Soviet medals and badges awarded to the liquidators.
Chernobyl disaster management included thousands of occupations, positions and tasks, particularly including the following case examples:
Personnel of the reactors: Yuri Korneev and Boris Stolyarchuk are the last surviving members of the Reactor No. 4 shift that were on duty at the moment of the catastrophe. Anatoly Dyatlov, who was in charge of the safety experiment at Reactor No. 4, died in 1995 of a heart attack. Alexander Yuvchenko died in 2008 at the age of 47. It is unknown if it was because of his leukemia, caused by the incident.
Firefighters who immediately responded to the reactor accident
Civil defense troops of the Soviet Armed Forces who intensively worked on the removal of contaminated materials and deactivation on the reactor itself and all affected territories
Various civilian scientists, engineers, and workers involved in all stages of the disaster management
A team of coal miners who built a large protective foundation to prevent radioactivity from entering the aquifer below the reactor.
Media and performing arts professionals who risked their lives to document the disaster on the ground and provide on-site entertainment events for the liquidators
Photographers Igor Kostin and Volodymyr Shevchenko are credited with taking the most immediate and graphic pictures of the destroyed reactor and first months of the relief operation, including photos of liquidators conducting highly-hazardous manual tasks.
A small number of foreigners (mostly from the Western countries) volunteered to participate in international medicine- and science-related on-the-ground projects related to the relief operation. Technically, they may also qualify for liquidator status depending on their exact location and tasks at the time of participation.
Exposures and health effects experienced by liquidators
According to the WHO, 240,000 recovery workers were called upon in 1986 and 1987 alone. Altogether, special certificates were issued for 600,000 people recognising them as liquidators.
Total recorded doses to individual workers in Chernobyl recovery operations during the period through 1990 ranged from less than 10 millisieverts (less than 1 rem) to more than 1 sievert (100 rems), due primarily to external radiation. The average dose is estimated to have been 120 millisieverts (12 rem) and 85% of the recorded doses were between 20 and 500 millisieverts (2 to 50 rems). There are large uncertainties in these individual doses; estimates of the size of the uncertainty range from 50% to a factor of five and dose records for military personnel are thought to be biased toward high values. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) estimates the total collective dose to the total of about 530,000 recovery operations workers as about 60,000 person-sieverts (6,000,000 person-rem).
According to Vyacheslav Grishin of the Chernobyl Union, the main organization of liquidators, "25,000 of the Russian liquidators are dead and 70,000 disabled, about the same in Ukraine, and 10,000 dead in Belarus and 25,000 disabled", which makes a total of 60,000 dead (10% of the 600,000 liquidators) and 165,000 disabled.
Estimates of the number of deaths potentially resulting from the accident vary enormously: the World Health Organization (WHO) suggest it could reach 4,000:
A total of up to 4000 people could eventually die of radiation exposure from the Chernobyl nuclear power plant (NPP) accident nearly 20 years ago, an international team of more than 100 scientists has concluded.
As of mid-2005, however, fewer than 50 deaths had been directly attributed to radiation from the disaster, almost all being highly exposed rescue workers, many who died within months of the accident but others who died as late as 2004.
Ivanov et al. (2001)  studied nearly 66,000 liquidators from Russia, and found no increase in overall mortality from cancer or non-cancer causes. However, a statistically significant dose-related excess mortality risk was found for both cancer and heart disease.
Rahu et al. (2006)  studied some 10,000 liquidators from Latvia and Estonia and found no significant increase in overall cancer rate. Among specific cancer types, statistically significant increases in both thyroid and brain cancer were found, although the authors believe these may have been the result of better cancer screening among liquidators (for thyroid cancer) or a random result (for brain cancer) because of the very low overall incidence.
While there is rough agreement that a total of either 31 or 54 people died from blast trauma or acute radiation syndrome (ARS) as a direct result of the disaster, there is considerable debate concerning the accurate number of deaths due to the disaster's long-term health effects, with estimates ranging from 4,000 (per the 2005 and 2006 conclusions of a joint consortium of the United Nations and the governments of Ukraine, Belarus, and Russia), to no fewer than 93,000 (per the conflicting conclusions of various scientific, health, environmental, and survivors' organizations).
Liquidators' issues 20 years after (2006)
Part of a monument to the liquidators near the Chernobyl site
The 20th anniversary of the Chernobyl catastrophe in 2006 was marked by a series of events and developments.
The liquidators held a rally in Kiev to complain about deteriorated compensation and medical support. Similar rallies were held in many other cities of the former Soviet Union.
The liquidators who reside in Estonia (some 4,200 as reported in 2006, 3,140 as of 2011) may hope for the introduction of an Estonian law for their relief after the meeting of their representatives with the President of Estonia on April 26, 2006. It turns out that by Estonian laws, the state may provide help and relief only to citizens, who are "legal descendants" of the citizens of 1918–1940 Republic of Estonia. At the same time, Russia, Belarus and Ukraine do not provide any relief to the liquidators residing abroad. The problem is tied to the fact that Chernobyl veterans are classified under the Estonian Persons Repressed by Occupying Powers Act. As of 2011 the issue has not yet been resolved.
The most highly exposed clean-up workers were significantly more symptomatic on the somatization and PTSD symptom scales. The workers with the greatest exposure reported more impairment than the two less-exposed groups, especially on the PTSD measures. Consistent with the findings of The Chernobyl Forum (2006) and with findings from other disasters involving radiation, the results show that the accident had a deleterious effect on mental health.
A number of military liquidators residing in Khabarovsk (Russia) were denied a certain compensation for loss of health on grounds that they were not salaried workers, but rather under military order. They have to appeal to the European Court of Human Rights.
Chernobyl Museum Liquidator Remembrance Book
The National Chornobyl Museum in Kiev, Ukraine supports the "Remembrance Book" (Ukrainian: Книга пам'яті, Kneega Pahmyati) – an open to the public online database of liquidators featuring personal pages with photo and brief structured information on their input. Data fields include "Radiation damage suffered", "Field of liquidation activity" and "Subsequent fate". The project started in 1997, containing over 5000 entries as of February, 2013. The database is currently available in Ukrainian language only.
^Ivanov, V. K.; Gorski, A. I.; Maksioutov, M. A.; Tsyb, A. F.; Souchkevitch, G. N. "Mortality Among the Chernobyl Emergency Workers: Estimation of Radiation Risks (Preliminary Analysis)." Health Physics: November 2001 - Volume 81 - Issue 5 - pp 514-521
^Rahu, M., Rahu, K., Auvinen, A., Tekkel, M., Stengrevics, A., Hakulinen, T., Boice, J. D. and Inskip, P. D. (2006), Cancer risk among Chernobyl cleanup workers in Estonia and Latvia, 1986–1998. Int. J. Cancer, 119: 162–168. doi: 10.1002/ijc.21733