When the roof of reactor no. 4 blew off in an uncontrolled explosion on April 26, 1986, a plume of radioactivity was released into the atmosphere – dousing the local area in radioactive materials before heading west to Belarus and as far as Cumbria, England. The reactor continued to leak for 10 days after the initial accident, releasing even more radiation into the environment as the first responders and liquidators worked to stymie the flow of chemicals.
Approximately 116,000 people were evacuated in the immediate aftermath (more than 250,000 in total) as authorities established a 30-kilometer (18.6-mile) no-go zone around the site.
Thirty-one clean-up workers are reported to have died from radiation exposure, and the World Health Organization (WHO) predicts the accident will have been responsible for 4,000 deaths in the long-term. (Though the true death count is hard to calculate).
The incident at Chernobyl is still considered to be the worst nuclear disaster to date. According to the World Economic Forum (WEF), the amount of radioactive material released was 400 times greater than that from the atomic bomb dropped on Hiroshima. Oleksiy Breus, an engineer at the site just hours after the event, described the effects of radiation exposure to the BBC.
"Radiation exposure, red skin, radiation burns and steam burns were what many people talked about but it was never shown like this," he said. "When I finished my shift, my skin was brown, as if I had a proper suntan all over my body. My body parts not covered by clothes – such as hands, face and neck – were red."
HBO’s "Chernobyl" is (at the time of writing) the highest-ranking drama program on IMDb, and ties for top place across all genres with "Blue Planet II". It’s not only the critics who have applauded the piece but the people who had to witness the disaster play out first hand. Eye-witnesses and first responders have since praised the painstaking accuracy of the drama both in terms of Soviet life and the effects of the radiation.
But today, 33 years on, it is a different story. The abandoned city of Chernobyl has become a holiday destination, enticing travelers and Instagrammers with its eerie beauty, tragic history, and photo-op potential. Two hotels, though Soviet in their simplicity, offer visitors a comfortable stay, while the Ukrainian government has announced plans to turn it into an official tourist destination.
Needless to say, exploring the ruins of the old Ukrainian town doesn't pose an immediate health risk. While there are certain areas of the exclusion zone worth giving a wide berth (see: the power plant and Red Forest), the vast majority of the zone (9 percent of it, or thereabouts) contain no more radioactivity than places of elevated natural radiation like Colorado and Cornwall, said Jim Smith, a professor of environmental science at the University of Portsmouth, to IFLScience.
"Natural radiation worldwide varies – if you're living at high altitudes, you get more cosmic radiation," said Smith. "For most of the exclusion zone, the doses that you would get living there are within that range of variability of radiation doses worldwide."
To break it down into numbers: Many of the liquidators (or first responders) who were called in to clean up the leak in 1986 were exposed to doses of around 800,000 to 160,000 microsieverts (µSv)*. That is extremely high and more than enough to cause vomiting, internal bleeding, and death within weeks of exposure. But the average annual dosage above natural background across much of the zone today is only around 1,000 µSv*.This is lower than the instant radiation you would receive if you were to go in for a whole-body CT scan (10,000 µSv*). [*Figures are based on calculations published by the BBC.]
That's most of the exclusion zone but not all. There are various "hotspots" that contain significantly higher rates of background radiation. Take, for example, the Red Forest, where you would receive an approximate dose rate of 350,000 µSv a year.
"It wouldn't be right to say that it's lethal, but if you lived there, you would get a pretty significant radiation dose that could lead to cancer in later life," said Smith, who predicts it will take around 300 years for radiation levels to return to normal in the Red Forest.
But it's not only levels of radiation that are important here, but the type of radiation. Over 100 radioactive elements were thrown into the atmosphere during the explosion but – thankfully – most of these had a relatively short half-life. Iodine-131 was one of the most harmful and is strongly linked to thyroid cancer. Yet, it decays incredibly quickly (relatively speaking), boasting a half-life of just eight days.
Most of the additional thyroid cases associated with Chernobyl (approximately 5,000 in total) can be traced to high levels of iodine-131 in the environment following the leak. The radioactive element seeped into the food chain, contaminating crops and animal produce locals continued to consume for weeks afterward.
While the supplementary iodine-131 will have all but disappeared from the zone by now, other elements – like strontium-90 and cesium-137 – with longer half-lives (29 and 30 years, respectively) will linger on. This means that 33 years after the event, there is still a lot of the decay process to go.
Plutonium-239 has an even longer half-life, lasting just over 24,000 years. The good news, says Smith, is that it isn't very bioavailable, meaning it is much less likely to be absorbed by plants and the soil. There was also less of it emitted in the first place.
All this is to say that if you were to live in the Chernobyl exclusion zone today, not very much would happen. Though you might need to sprinkle an extra layer of fertilizer to increase crop yield, jokes Smith, who says he'd prefer to see it remain a nature reserve. [On a side note: Wildlife in the area are flourishing thanks to the absence of humans.]
In fact, people do already live there, with some communities returning the year of the explosion – as of 2000, there were approximately 200 people living within the exclusion zone.