CHEMCO Exit Exam • Set 13 Question 19 of 30

While testing a cargo tank, your oxygen indicator reads 25% oxygen in the tank. You would then

✓

Direct Answer

Option B: suspect the accuracy of the reading

A normal atmospheric oxygen level is approximately 20.9%. An oxygen indicator reading of 25% is significantly above this, suggesting an instrument malfunction or calibration error. As per ISGOTT, instrument accuracy is paramount for safety, so the reading should be immediately suspected and verified.

All Options

enter the tank safely

suspect the accuracy of the reading (Correct Answer)

ventilate the tank

test for nitrogen

Detailed Explanation & Context

Relevant Framework: STCW 2010 Manila Amendments • DG Shipping E-Learning & Exit Exam Standards • Advanced Training for Chemical Tanker Cargo Operations (CHEMCO).

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