Fact check: At what depth does nitrogen narcosis typically occur in scuba diving?

1. Summary of the results

Based on the scientific analyses, nitrogen narcosis typically becomes noticeable at depths around 30 meters (98 feet) ^{[1] [2]}. However, the onset and severity of nitrogen narcosis varies significantly among individual divers and depends on the specific depth reached.

The research shows a progressive depth-related pattern:

• 10-20 meters: Initial impairment of mental and physical tasks may begin, though symptoms are generally benign and difficult to recognize ^[3]
• 30 meters (98 feet): This represents the threshold where nitrogen narcosis becomes noticeable for most divers ^{[1] [2]}
• 60-70 meters: All divers experience significant impairment when breathing compressed air at these depths ^[2]
• 90 meters: Represents the narcotic limit for diving on air ^[3]

Symptoms progress from mild effects like light-headedness and euphoria at shallower depths ^[4] to severe impairment including confusion, disturbed coordination, hallucinations, and potential unconsciousness at greater depths ^[3].

2. Missing context/alternative viewpoints

The original question lacks several important contextual factors that significantly influence nitrogen narcosis onset:

• Individual variability: The analyses emphasize that narcosis effects are highly variable among divers ^[2], meaning some individuals may experience symptoms at shallower depths while others remain less affected
• Breathing gas composition: The depth thresholds primarily apply to compressed air diving - different gas mixtures would alter these parameters ^[2]
• Safety margins in training: Most recreational diving agencies limit depths to 18-20 meters specifically to avoid significant narcosis risks ^[1], indicating that the industry prioritizes safety well below the typical onset depth
• Post-dive effects: Research shows that narcotic effects can persist after diving and may be mitigated through oxygen administration during decompression ^[5]

3. Potential misinformation/bias in the original statement

The original question itself does not contain misinformation, as it appropriately asks for the typical depth range rather than making false claims. However, any response that provides only a single depth figure without acknowledging the significant individual variability and progressive nature of nitrogen narcosis would be misleading.

The scientific consensus clearly establishes that while 30 meters serves as a general threshold for noticeable effects ^{[1] [2]}, the condition can manifest as early as 10 meters in some individuals ^[3] and becomes universally significant only at much greater depths of 60-70 meters ^[2].