# Oxygen Deficiency #safety #gas-hazard #oxygen Oxygen deficiency occurs when oxygen levels drop below 19.5%, creating a dangerous condition that can cause hypoxia, loss of consciousness, or death. ## Definition - Normal oxygen: ~20.9% - Oxygen deficiency: < 19.5% - Critical level: < 16% - Immediate danger: < 10% ## Causes - Displacement by other gases (N2, CO2, Ar) - Consumption by combustion - Confined spaces - Poor ventilation ## Effects - **19.5-16%**: Impaired judgment, fatigue - **16-12%**: Increased breathing, accelerated heartbeat - **12-10%**: Poor judgment, blue lips - **<10%**: Unconsciousness, death ## Detection - Oxygen sensors/monitors - Measured as %Vol or %v/v - Critical for confined space entry - Continuous monitoring in risk areas ## Prevention - Proper ventilation - Oxygen monitoring - Confined space procedures - Worker training - Emergency response plans ## Safety Standards - OSHA: < 19.5% requires protection - NIOSH: < 19.5% immediately dangerous - Industry standards vary by application ## Related Concepts - [[Oxygen Enrichment]]