Historically, coal miners used canaries as biological warning indicators to detect dangerous gases inside underground mines. Due to their high metabolic rate and rapid breathing, these birds were particularly vulnerable to toxic gases such as carbon monoxide.
When harmful gas concentrations increased, the canaries often showed distress or collapsed before miners were affected, alerting workers to evacuate. This practice gave rise to the expression “canary in a coal mine”, meaning an early indicator of impending danger.
APSC Relevance: Mine Safety, Environmental Indicators
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