High Risk of Catastrophe Remained
Although the immediate danger was reduced, the situation was far from secure. The reactor core continued burning, and the threat of it melting through the building to the groundwater remained a dangerous possibility.
To counteract this, the Soviets used all available liquid nitrogen, aiming to freeze the ground beneath Chernobyl to stop the fire from reaching the groundwater. Miners, lacking proper protection and using only hand tools to avoid damaging the plant, bravely worked, some succumbing to radioactive exposure.