When must an excavation atmosphere be tested?
Correct Answer
A) Before entry where oxygen deficiency or hazardous atmosphere could reasonably be expected.
OSHA requires testing where hazardous atmospheres could reasonably exist, such as near landfills or hazardous substances.
Why This Is the Correct Answer
OSHA requires testing where hazardous atmospheres could reasonably exist, such as near landfills or hazardous substances.
Why the Other Options Are Wrong
Option B: Test only after backfill is complete
Choice B (Only after backfill) is rejected because it leaves the work at an informal or incomplete stage, while Hazardous atmosphere excavation requires Before entry where oxygen deficiency or hazardous atmosphere could reasonably be expected.
Option C: Record only a midday air reading
In site construction, Only at lunch is the wrong selection for Hazardous atmosphere excavation: the option delays or omits the controlling step.
Option D: Assume excavation atmospheres never require testing on construction sites
The trap in D is Never in construction excavations. That selection is wrong because the choice would not get the project to Before entry where oxygen deficiency or hazardous atmosphere could reasonably be expected.
Memory Technique
Link hazardous atmosphere excavation to its book condition; a different condition means a different answer than Before entry where oxygen deficiency or hazardous atmosphere could reasonably be expected.
Reference Hint
Open OSHA 29 CFR 1926 Subpart P; EPA Construction General Permit concepts where applicable; use OSHA 1926.651(g) to confirm that OSHA requires testing where hazardous atmospheres could reasonably exist, such as near landfills or hazardous substances.
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