A worker must enter a confined space to perform maintenance. The space has been tested and found to have 19% oxygen content. What action should be taken?
Correct Answer
B) Entry is prohibited until oxygen level is corrected
OSHA requires oxygen levels in confined spaces to be between 19.5% and 23.5%. At 19% oxygen, the space is oxygen-deficient and entry is prohibited until the atmosphere is corrected.
Why This Is the Correct Answer
OSHA 29 CFR 1926.95 establishes that confined spaces must maintain oxygen levels between 19.5% and 23.5% for safe entry. At 19% oxygen, the space is classified as oxygen-deficient, creating an immediately dangerous to life and health (IDLH) atmosphere. Entry must be prohibited until the oxygen level is corrected through ventilation or other atmospheric controls. No worker should enter until testing confirms the oxygen level is within the acceptable range.
Why the Other Options Are Wrong
Option A: Entry is safe, no additional precautions needed
This is completely unsafe as 19% oxygen is below OSHA's minimum requirement of 19.5%, creating an oxygen-deficient atmosphere that poses serious health risks including unconsciousness and death.
Option C: Entry is allowed with continuous air monitoring
While continuous air monitoring is a good safety practice, it does not address the fundamental problem that the oxygen level is already below the minimum safe threshold of 19.5% required by OSHA.
Option D: Entry is allowed with supplied air respirators only
Even with supplied air respirators, OSHA prohibits entry into oxygen-deficient atmospheres until the atmospheric conditions are corrected, as equipment failure could be fatal in such conditions.
Memory Technique
Remember '19.5 to Stay Alive' - oxygen must be at least 19.5% or entry is prohibited. The given 19% is below this critical threshold.
Reference Hint
OSHA 29 CFR 1926.95 - Personal Protective Equipment, and confined space entry standards in safety reference materials
More Project Mgmt Questions
What is the minimum R-value required for wall insulation in Florida Climate Zone 2?
A subcontractor brings a new chemical product to your jobsite. Under the Globally Harmonized System (GHS), what information must be immediately available to workers?
A construction site has a trench that is 8 feet deep in Type B soil. What is the maximum allowable slope ratio for the trench walls without protective systems?
A detail drawing shows a scale of 3/4" = 1'-0". If a dimension measures 2.25 inches on the drawing, what is the actual dimension?
What is the maximum recommended spacing between drywall screws when attaching to wood studs?