A confined space has an oxygen reading of 18%, hydrogen sulfide at 8 ppm, and carbon monoxide at 30 ppm. What is the entry status?
Correct Answer
C) Entry prohibited - oxygen deficient
The oxygen level of 18% is below the required minimum of 19.5%, creating an oxygen-deficient atmosphere. Entry is prohibited until the atmospheric conditions are corrected, regardless of other acceptable gas readings.
Why This Is the Correct Answer
OSHA 29 CFR 1926.95 requires a minimum oxygen concentration of 19.5% for safe entry into confined spaces. At 18%, this atmosphere is oxygen-deficient and creates an immediate danger to life and health. Entry is absolutely prohibited regardless of other gas readings being within acceptable limits. The space must be ventilated and retested until oxygen levels reach at least 19.5% before any entry can be considered.
Why the Other Options Are Wrong
Option B: Entry permitted with supplied air respirators only
While supplied air respirators could theoretically provide safe breathing air, OSHA regulations prohibit entry when oxygen is below 19.5% until atmospheric conditions are corrected
Option D: Safe for entry with standard PPE
Standard PPE cannot protect against oxygen deficiency - workers would still be breathing oxygen-deficient air which can cause unconsciousness and death
Memory Technique
Think '19.5 to Stay Alive' - below 19.5% oxygen means no entry, period
Reference Hint
OSHA 29 CFR 1926.95 - Personal Protective Equipment, Confined Space Entry requirements
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