When a worker must enter a transformer tank, if the concentration of oxygen is less than ____%, it could be a health threat to the worker.
A) 10
B) 20
C) 60
D) 75

Question

Quizplus · Accepted Answer

The normal concentration of oxygen in the air is approximately 21%. If the concentration of oxygen drops below 19.5%, it is considered to be oxygen-deficient and can pose a health threat to workers, making option B (20%) the correct choice.

When a Worker Must Enter a Transformer Tank, If the Concentration