10 free CHST practice questions in the real exam format, covering the official content areas, with an explanation for every answer.
CHST Practice Test 6Tutor mode
Question 1 of 10
Hazard and Risk Identification and Control
A pre-entry test in a storm-sewer junction box gives these readings: oxygen 20.2%, combustible gas 12% LFL, carbon monoxide 5 ppm and hydrogen sulfide 0 ppm. Under 29 CFR 1926 Subpart AA, which reading makes the atmosphere hazardous?