A notable chapter in the history of mining came to a close on this day in 1986: it was announced that canaries kept for use in coal mines were to be made ‘redundant’.
The government announced that over 200 of the birds - used to detect the presence of harmful gases underground - would be phased out from pits across the UK throughout the following year.
Coal miners had taken canaries into mines for decades to act as an as an early-warning signal for carbon monoxide and other toxic gases. The animals’ size, high metabolism and rapid breathing rate made them more susceptible than humans to the gases.
Signs of sickness or distress in the birds would usually allow miners enough time to head for safety or put on respiratory equipment.
But from 1986, electronic detectors replaced the canaries for reasons of cost - and because they were likely to be more effective at indicating the presence of pollutants in the air in a timely manner.