CMC Hazardous Materials Management & Containment 3

Question 1

Which gas detection instrument is most appropriate for measuring hydrogen sulfide (H₂S) at sub-ppm concentrations in a confined marine space?

Accepted Answer

Electrochemical sensor calibrated for H₂S

Answer

Electrochemical sensors are specifically designed for toxic gas detection at low ppm and sub-ppm levels, making them ideal for H₂S monitoring.

Question 2

In a marine environment, a photoionization detector (PID) is primarily used to detect:

Accepted Answer

Volatile organic compounds at low concentrations

Answer

PIDs ionize molecules with UV light to detect volatile organic compounds (VOCs) at trace concentrations, far below LEL thresholds.

Question 3

When calibrating a multi-gas detector for confined space work on a tanker, the calibration gas mixture should reflect:

Accepted Answer

The specific hazards likely encountered, using certified standard gas

Answer

Calibration gas must be a certified standard mixture matching the anticipated hazardous gases to ensure accurate field readings.

Question 4

A Certified Marine Chemist discovers that a previously certified Safe-for-Hot-Work tank has been disturbed by cargo loading operations. The correct action is to:

Accepted Answer

Re-test the atmosphere before issuing a new certificate or extending work

Answer

Any significant disturbance that may alter atmospheric conditions invalidates the prior certification, requiring re-testing and re-issuance.

Question 5

Which personal protective equipment (PPE) level is required when the specific hazardous substances and concentrations in a marine confined space are unknown?

Accepted Answer

Level A — fully encapsulating vapor-protective suit with SCBA

Answer

Level A provides maximum skin, eye, and respiratory protection and is required when the hazard is uncharacterized or when highest protection is needed.

(CMC) Certified Marine Chemist Practice Test

(CMC) Certified Marine Chemist Practice Test

CMC Hazardous Materials Management & Containment 3