🔍 Key Concepts

• Sour crude and what makes it different from sweet crude • Toxic gases commonly associated with crude oil production and transport • Health effects and detection requirements for hydrogen sulfide (H2S) per safety guidance

💭 Think About

• Think about which listed substance is most characteristically associated with sour crude oil • Consider which of these gases is immediately dangerous to life and health at low concentrations in enclosed spaces like pump rooms • Ask yourself: which of these is most likely to accumulate in a cargo pumproom atmosphere when handling sour crude?

✅ Before You Answer

• Verify which substance is specifically linked to sour (high-sulfur) crude oil • Check which gas requires special fixed or portable detectors on tankers carrying sour crude cargoes • Confirm which option is known for a strong, characteristic odor at low levels but loss of smell at higher, dangerous levels