What happened during the confined space incident involving a diver?

• A. A diver lost consciousness due to a nitrogen blanket and fell; the backup diver also lost consciousness and drowned.
• B. Both divers were rescued unharmed.
• C. Only the backup diver was harmed.
• D. The diver remained conscious after the incident.

Answer: (A)

In a confined-space diving situation, the amount of breathable oxygen in the surrounding gas is what keeps a diver conscious. A nitrogen blanket can push out or dilute the oxygen, creating a rapidly oxygen-deprived environment. When the first diver inhaled this oxygen-poor mixture, consciousness was lost and he fell. Because the atmosphere remained unsafe, the standby or backup diver could not effectively intervene and also became incapacitated, leading to drowning. This sequence shows why the described outcome is that both divers were harmed and one did not survive, rather than both being unharmed, only one harmed, or the diver staying conscious. It underscores the importance of breathable gas monitoring, proper ventilation, and a ready rescue plan with trained personnel.