SafetyQuestion 458 of 521
Before entering a permit-required confined space, the atmosphere should be tested in what order?
a.Toxic gases first, then oxygen, then flammables
b.Oxygen first, then flammable gases/vapors, then toxic air contaminants
c.Flammables first, then oxygen, then toxics
d.No testing is needed if a fan is running
Explanation
Atmospheric testing is done in the order oxygen, flammability, then toxicity, because most flammable and toxic sensors depend on a known oxygen level to read correctly. Reversing the order can give false readings, and running a fan does not substitute for testing before entry.
Law Reference: Cal/OSHA Title 8 §5157Practice all 521 questions free — no signup required.
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