The explosion caused the release of a massive amount of radiation to be released into the environment.

  1. A massive amount of radioactive debris escaped in the first explosion.

  2. Air then rushed into the reactor causing the graphite rods and other material to catch fire.

30 people died almost immediately due to the explosion or intense doses of radiation.

200 people were seriously injured by radiation.

  1. The reactor had been running for 2 years continously and therefore there was a large build up of plutonium and other fission products.

Approximately 5% of the total radioactivity escaped over the next 10 days.

  1. Boron carbide, magnesium carbonate, clay and lead were dropped on the burning reactors using helicopters in order to stifle the fire and stop any chain reactions. However, the fire burnt through and was only finally quenched using nitrogen and water.

Many of the fuel rods and cooling pipes had fused and melted through the concrete base of the reactor. They had formed a glassy mass in the enclosed cavity below the reactor.