A Soviet soldier prepares for work, removing reactor debris from a roof in Chernobyl, 1986.
The extraordinarily high levels of radiation on the roofs surrounding the plant, in some cases surpassing 1000 Roentgens/hour, fouled the electronics of the robots used to clear the reactor debris strewn across the roofs. Due to this, soldiers were used in their place (dubbed ‘bio-robots’). The soldiers were only be able to work outside for a minute at most, mere seconds in some of the worst areas, before receiving a potentially lethal dose. They lacked effective protective equipment and were not made fully aware of the severe health consequences of their work. (Sources, V.M. Chernousenko. A. Yaroshinskaya. Both entitled 'Chernobyl'.)