CHST CHST - Construction Health and Safety Technician Excavation and Trenching Safety Questions and Answers 4

Question 1

Which atmospheric condition in an excavation requires air monitoring BEFORE workers enter?

Accepted Answer

Excavation is more than 4 feet deep AND oxygen-deficient or hazardous atmospheres may be present

Answer

OSHA 29 CFR 1926.651(g) requires testing for hazardous atmospheres in excavations deeper than 4 feet where such conditions may reasonably be expected.

Question 2

A utility strike occurs during excavation. Which action should be taken FIRST?

Accepted Answer

Stop work, remove workers, and notify the utility owner

Answer

Worker safety is paramount — immediately stop work, evacuate all personnel, and then notify the utility company to assess and control the hazard.

Question 3

Under OSHA standards, how often must a competent person inspect an excavation?

Accepted Answer

Before each work shift and after any event that could affect its integrity

Answer

OSHA 29 CFR 1926.651(k) requires inspection by a competent person before each shift and after any rain, freeze/thaw, or other potentially hazardous event.

Question 4

What is the required minimum oxygen concentration level for workers to safely enter a trench or excavation?

Accepted Answer

19.5%

Answer

OSHA defines an oxygen-deficient atmosphere as below 19.5% oxygen by volume; workers may not enter without respiratory protection below this level.

Question 5

When is a registered professional engineer (PE) required to design a protective system for an excavation?

Accepted Answer

Tabulated data or manufacturer data is not available for the site conditions

Answer

A PE-designed system is required when site conditions fall outside the scope of OSHA Appendix tables or manufacturer-supplied tabulated data under 29 CFR 1926.652(b)(4).

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Practice Test

CHST CHST - Construction Health and Safety Technician Excavation and Trenching Safety Questions and Answers 4