Accumulations of H2S gas on a MODU can be dangerous. It is imperative that personnel know that H2S gas possesses which of the listed characteristics?

Correct Answer: Option B — heavier than air

Hydrogen sulfide (H2S) has a vapor density of approximately 1.19, making it significantly heavier than air. Consequently, this hazardous gas accumulates in low-lying spaces, enclosed compartments, bilges, and mud pits on Mobile Offshore Drilling Units (MODUs), posing extreme asphyxiation and toxicity risks to unmonitored personnel.