A technician is preparing to enter a walk-in cooler that has been isolated for several days after an R-404A leak. Atmospheric testing reveals a normal oxygen level but elevated refrigerant concentration. What is the immediate safety concern and required action, according to typical confined space procedures?

Question: A technician is preparing to enter a walk-in cooler that has been isolated for several days after an R-404A leak. Atmospheric testing reveals a normal oxygen level but elevated refrigerant concentration. What is the immediate safety concern and required action, according to typical confined space procedures?

Answer options:

• Proceed with entry, as oxygen levels are normal. ✅ Ventilate the space and re-test before entry.
• Enter with an SCBA, as the refrigerant is highly toxic.
• Seal the space to contain the refrigerant and call for emergency services.

Correct answer: Ventilate the space and re-test before entry.

Explanation: Even with normal oxygen levels, elevated refrigerant concentrations can pose health hazards from toxicity or displacement if allowed to build up again, and also indicates a potential leak source. Provincial OHS regulations for confined spaces require ventilation to remove contaminants and reduce risks to acceptable levels before entry, followed by re-testing. R-404A has an A1 safety classification, meaning lower toxicity, but high concentrations are still dangerous.