A forest fire is still burning across more than 1,200 hectares in the Chornobyl Radiation and Ecological Biosphere Reserve after two Russian Shahed-type drones crashed in the exclusion zone, with caesium 137 now detected in air sampled near the burn area. That is according to Ukraine’s State Nuclear Regulatory Inspectorate (SNRIU), which on Saturday confirmed that the radionuclide reading remains almost 1,200 times below the country’s permissible safety threshold.
Although operational data from the State Enterprise EKOCENTER recorded caesium 137 in air sampled 30 to 150 metres from active burning at 680 microbecquerels per cubic metre, that figure remains well below the 0.8 becquerels per cubic metre maximum permissible under Ukraine’s Radiation Safety Standards. The regulator attributed the elevated reading to the substantial volume of timber and vegetation now burning across the reserve.
“The radiation situation… remained under control,” the SNRIU said, with gamma-dose rates across the rest of Ukraine remaining within long-term monitoring ranges.
Although Ukrainian authorities had initially expected to bring the fire under control by Friday afternoon, dry weather, strong winds and unexploded ordnance left from the war have forced rescuers to suspend operations across multiple forested sections of the zone, with Russian drones continuing to hover over the territory and impede the firefighting response. Chernihiv regional governor Vyacheslav Chaus has separately estimated the burn area at up to 40 square kilometres, with more than 331 personnel and 75 pieces of equipment now committed to the response.
Reserve scientist Denys Vyshnevskiy has confirmed personnel are tested for radionuclide concentrations in their bodies after each shift on the fire line.
“Guys… are breathing air with high concentration of radionuclides,” Vyshnevskiy said.
It comes as Wood Central reported in October 2024 that fires deep inside the exclusion zone had previously caused a spike in caesium 137 readings as far away as Norway’s Arctic monitoring stations, with the Norwegian Radiation and Nuclear Safety Authority detecting elevated levels at its Svanhovd and Viksjoefjell outposts when air masses moved across the Baltic. Saturday’s regulatory assessment treats the dispersal of long-buried radionuclides through combustion products as a redistribution of activity already present in the ecosystem rather than a new source of contamination.
The Chornobyl Exclusion Zone, which covers around 2,800 square kilometres of northern Ukraine and now ranks as the third-largest nature reserve in mainland Europe, has remained largely uninhabited since the catastrophic 1986 nuclear meltdown. The disaster created a richer ecosystem, with biodiverse primary forests gradually replacing monoculture pine plantations across the zone over the following four decades.
That ecosystem is now under sustained pressure from Russia’s war, with Wood Central previously revealing that more than 3.5 million hectares of Ukrainian forests have been damaged or destroyed since the February 2022 invasion, and that crime syndicates are felling and trafficking timber from inside the exclusion zone itself. Ukrainian authorities last year charged a logging company director with illegally clearing more than 1,000 trees from inside the Red Forest deep within the 30-kilometre zone, with the proceeds laundered through European furniture markets.
Although the 2020 Chornobyl wildfires burned for several weeks and caused a measurable spike in background radiation across northern Ukraine, the SNRIU has assessed that the current event is unlikely to push concentrations beyond control levels for populations outside the zone. Rain forecast for late Saturday was expected to assist firefighting efforts, with the latest fire following a 2025 Russian drone strike that punctured the New Safe Confinement shelter protecting the reactor destroyed in the April 1986 disaster.
