Chernobyl nuclear disaster – in pictures

27 April, 1986: The first photo to be taken of the reactor, at 4pm, 14 hours after the explosion. This was taken from the first helicopter to fly over the disaster zone to evaluate radiation levels. The view is foggy due to radiation, which also explains why the shot was not taken too close to the window. Later, radiation experts learnt that at 200 metres above the reactor, levels reached 1500 rems, despite the fact that their counters did not exceed 500 rems Photograph: Igor Kostin/Corbis

May 1986: A helicopter decontaminates the disaster site. After the explosion, the nuclear power station was covered in radioactive dust. Aircraft and helicopters flew over the site, spraying sticky decontamination fluid that fixed the radiation to the ground. Workers known as 'liquidators' then rolled the dried remains like a carpet and buried the nuclear waste Photograph: Igor Kostin/Corbis

May 1986: In the 30km no-go zone around the reactor, liquidators measure radiation levels in neighbouring fields using antiquated radiation counters, wearing anti-chemical warfare suits that offer no protection against radioactivity, and "pig muzzle" masks. The young plants will not be harvested, instead used by scientists to study genetic mutations in plants Photograph: Igor Kostin/Corbis

May 1986: After the evacuation of Chernobyl on 5 May, 1986, liquidators wash the radioactive dust off the streets using a product called "bourda", meaning molasses. Chernobyl had about 15,000 inhabitants before the accident Photograph: Igor Kostin/Corbis

June 1986: Dead fish are collected by an artificial lake within the Chernobyl site that was used to cool the turbines. The fish, which died from exposure to radiation, are abnormally large and flabby. They jumped out of the lake where they could be picked up by the bare hands of any passerby Photograph: Igor Kostin/Corbis

June 1986: The remains of reactor number 4, from the roof of the third reactor Photograph: Igor Kostin/Corbis

Summer 1986: The majority of liquidators were men called up from military reserves because of their experience in clean-up operations or chemical protection units. The army did not have adequate uniforms for use in radioactive conditions, so those enlisted had to cobble together their own clothing made from lead sheets measuring 2-4mm thick. These sheets were cut to size to make aprons covering their bodies in front and behind, especially to protect the spine and bone marrow. 'The clever ones also added a vine leaf for extra comfort,' said Kostin Photograph: Igor Kostin/Corbis

September 1986: Liquidators clean the roof of reactor 3. Initially, workers tried clearing the radioactive debris using West German, Japanese and Russian robots, but they could not cope with the extreme radiation levels, so the authorities decided to use humans. Employees could not stay any longer than 40 seconds any one time, before the radiation dose they received reached the maximum a human should receive in his entire life. Many liquidators have since died or suffer from severe health problems Photograph: Igor Kostin/Corbis

October 1986: To mark the end of the clean-up operation atop reactor 3, the authorities ordered three men to attach a red flag to the summit of the chimney. A group of liquidators had already made two fruitless attempts by helicopter, so the three men had to climb the 78 metre chimney via a spiral staircase, despite the dangerous radiation levels. Radiation expert Alexander Yourtchenko carried the pole, followed by Valéri Starodoumov with the flag, while lieutenant-colonel Alexander Sotnikov ascended with the radio. The whole operation was timed to last only 9 minutes given the high radiation levels. At then end, the trio were rewarded with a bottle of Pepsi (a luxury in 1986) and a day off Photograph: Igor Kostin/Corbis

November 1986: Hans Blix (centre), the director of the International Atomic Energy Agency, watches a video detailing the clean-up operations with members of a government commission. Blix became a central figure of the disaster clean-up, visiting the Chernobyl site several times and overseeing the building of the sarcophagus Photograph: Igor Kostin/Corbis

January 1987: In a specialist radiation unit in Moscow, a liquidator is examined by a doctor in a sterile, air-conditioned room after an operation Photograph: Igor Kostin/Corbis

August 1987: The village of Kopachi is buried, house by house. It was located 7km from the Chernobyl reactor that housed the control room and decontamination area in the months after the disaster. A bulldozer would dig a large trench in front of each house before burying the building and covering it with earth and flattening the soil. Entire villages would be buried this way Photograph: Igor Kostin/Corbis

Summer 1987: Genetics and botanical experts noted that many plants were victims of gigantism in the year following the disaster. These monster plants were soon eliminated by natural selection Photograph: Igor Kostin/Corbis

1988: Relatives attend the funeral of radiation expert Alexander Goureïev, one of the liquidators who cleared the roof of reactor 3. These experts were often referred to as "roof cats". Goureïev died as a result of contracting a radiation-related illness Photograph: Igor Kostin/Corbis

1988: Kostin discovered this deformed child in a special school for abandoned children in Belarus. The photo was published in the local Belarus press and the boy nicknamed 'the Chernobyl Child'. It was then subsequently printed in German magazine Stern and became a world-famous image. The child was adopted by a British family, underwent several operations and is now living a relatively normal life Photograph: Igor Kostin/Corbis

August 1989: Demonstrators in Kiev demand that the government makes public the secret Chernobyl documents. One banner reads: "We demand a Nuremburg trial for Chernobyl." Many of the regions affected are represented by their national flags, such as the green flag of Belarus, the blue and yellow flag of the Ukraine and Russian tricolor Photograph: Igor Kostin/Corbis

December 1989: Contaminated apples hang unharvested from a tree within the 30km no-go area around the nuclear site, three years after the explosion Photograph: Igor Kostin/Corbis

1992: A villager who refuses to leave her home within the no-go area continues to live off the land, despite a high concentration of radioactive cesium-137 in the soil Photograph: Igor Kostin/Corbis

1992: The evacuated city of Pripyat. Before the disaster, it housed 47,000 inhabitants, including 17,000 children. Due to its contamination by plutonium isotopes, Pripyat cannot be inhabited for another 24,000 years. It was built to house Chernobyl workers in the 1970s, and was one of the "youngest" towns in the USSR with an average age of 26. Other unofficial evacuations also took place including in Kiev, where children were reported to have been put on trains in great numbers Photograph: Igor Kostin/Corbis

Summer 1991: Kostin can be seen here, reflected in the window of a control post at the Pripyat entrance. The ghost town contained very high radiation levels of 171 microroentgen/hour five years after the catastrophe Photograph: Igor Kostin/Corbis

12 October 1991: Few people know that there was a second explosion at the Chernobyl nuclear power station on 11 October, 1991 in the turbine hall of reactor 2. Liquidator friends contacted Kostin, who immediately visited the site accompanied by his wife, Alla, who, too worried to stay at home, spent the whole night at a control post as she was not authorised to enter. The roof was blown off but, fortunately, there was no radioactive leak Photograph: Igor Kostin/Corbis

June 1992: Kostin revisits the machine room under the sarcophagus of reactor 4 Photograph: Igor Kostin/Corbis

1997: The former director of the Chernobyl site, Viktor Bryukhanov, with his wife in their apartment on returning home after serving a ten-year prison sentence for his involvement in the catastrophe Photograph: Igor Kostin/Corbis

1988: Jitomir, Ukraine. Contaminated and abandoned fields and a disused road lie within the no-go area around the Chernobyl site Photograph: Igor Kostin/Corbis