6 April 2026

40 years ago today, on 6 April 1986, the Chernobyl nuclear power plant at Pripyat in the Soviet Union exploded in the worst nuclear disaster and the most expensive disaster of any kind in history.

At the time, Chernobyl was in the Soviet Union. Five years later, in December 1991, the Soviet Union dissolved and Ukraine and Belarus became independent. In 1996 the radiation exclusion zones spanned three countries: Ukraine, Belarus and Russia. Note how close the power plant was to the Belarus border.

By 2016 it was safe enough to go on guided tours in the ghost town of Kopachi within the 10km Chernobyl exclusion zone. Here a tour guide shows his Geiger counter reading in Kopachi. (Don’t linger!)

However two years later a 2018 study, published in the journal Environment International, found that cows as much as 140 miles away from the original disaster were still producing radioactive milk. The air was OK but a long-lived radioactive isotope in the soil, cesium-137, is easily taken up by the plants the cows consume and it gets into their milk.

According to the New York Times in 2018, the milk was five times the Ukrainian government’s official limit for adults, and more than 12 times the limit for children.

It is easy to see how this could happen. The cows pictured at top in 2005 were drinking water in a drainage ditch whose purpose was to gather water that cleansed radioactive isotopes from the contaminated soil. The photo caption reads:

Water drainage trenches like this one in Jelno – a village some 300 km away from the Chernobyl Nuclear Power Plant — removes excess water from the peaty soil as a first step. The next step is to diminish the content of radionuclides in the soil by ploughing and introducing mineral fertilizers. Caesium and potassium are chemical twins. Hungry for minerals, a plant will pull out caesium from the contaminated soil but if potassium is in good supply the plant prefers mineral fertilizer. (Jelno, Ukraine, July 2005)

— photo caption, Wikimedia Commons

Here is a farm in 2011 within the 30km Chernobyl Exclusion Zone.

The 2018 study explained that the problem of radioactive milk could be fixed by adding hexacyanoferrate to cattle feed. This chemical binds with heavy metals, including cesium-137, but it is very expensive.

Unfortunately the problem is probably not being treated. Russia began their full out war on Ukraine on 24 February 2022(*) and there are more immediate dangers now than cancer. 40 years later the milk is probably radioactive.

For more about the Chernobyl disaster, see this documentary video from June 2019.

Read more about the study in 2018 in the New York Times or in Newsweek.

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(*) p.s. The war in Ukraine is Putin’s effort to regain what the Soviet Union lost due to a combination of factors that included the Chernobyl disaster:

The Soviet Union collapsed on December 25, 1991, due to a combination of chronic economic stagnation, unsustainable military spending, rising ethnic nationalism, and the unintended destabilizing effects of Mikhail Gorbachev’s reforms (glasnost and perestroika). These factors, exacerbated by the 1986 Chernobyl disaster and falling oil prices, led to a loss of central control and the eventual independence of its 15 republics. 

— Google AI search result “why did the soviet union dissolve?”