Question 1004 of 234 · California Wastewater Operator Exam
What is the minimum safe oxygen concentration in the air of a confined space before entry?
Exactly one answer is correct.
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Correct answer to question 1004
- D: 19.5 percent
Explanation
Air below 19.5 percent oxygen is considered oxygen deficient. Normal air is about 20.9 percent, so 19.5 percent is the lowest acceptable reading.
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