Human beings can display behaviours that deny the presence of danger.
Humans are prepared to accept health risks that are believed to be outweighed by the benefits of modern living. We know, for instance, that the fumes emitted by motor vehicles are associated with asthma, but cars have become too indispensable to ban. Likewise, we might take the view that plastics and pesticides are so essential to modern living that we are prepared to pay the potential price of an increasing incidence of testicular cancer and infertility.
On 13 November 1985 the ice cap of the high volcano above the town of Novado del Ruiz in Columbia exploded. The eruption melted snow fields, picked up debris and roared down the side of the volcano towards a number of villages. Scientists who had been monitoring the volcano warned village residents of the impending danger, but because it was raining, and the danger seemed far off, the majority of residents refused to leave their homes. That night 26,000 people died.