🔍 Key Concepts

• Behavior of hydrogen sulfide (H2S) gas in air • Relative vapor density of a gas compared to air • Typical toxicity and detectability of H2S on drilling units and MODUs

💭 Think About

• Consider whether dangerous gases on MODUs are more likely to accumulate high up or in low, enclosed spaces like pits and sumps. • Think about how serious H2S exposure is considered in offshore safety training: is it described as mild, or something more severe? • Ask yourself if relying on the gas’s color or smell would be considered a safe practice when dealing with H2S.

✅ Before You Answer

• Verify whether H2S tends to collect in low-lying areas or rise and disperse. • Check if H2S is classified as highly toxic or just mildly toxic in safety materials. • Confirm whether H2S is colorless or colored, and whether it can always be reliably detected by smell.