OSHA 30- Excavation Hazards, Soils
Questions and Answers | Latest Version
| 2024/2025 | Correct & Verified
What is a trench?
✔✔ A trench is an excavation that is deeper than it is wide, typically less than 15 feet wide.
How can water affect excavation safety?
✔✔ Water can weaken soil, increase the risk of cave-ins, and create hazardous conditions for
workers.
What must be in place before workers enter a trench deeper than 5 feet?
✔✔ A protective system such as sloping, shoring, or a trench box must be used.
Why should excavated soil (spoils) be kept away from the edge of a trench?
✔✔ Keeping spoils at least two feet from the edge prevents them from falling in and adding
pressure that could cause a collapse.
What is a trench shield?
1
,✔✔ A trench shield, also known as a trench box, is a protective structure that prevents workers
from being buried in a collapse.
What is benching in excavation?
✔✔ Benching involves cutting the sides of an excavation into steps to reduce the risk of cave-
ins.
How can vibrations affect excavation safety?
✔✔ Vibrations from heavy equipment, traffic, or machinery can cause soil to shift and increase
the risk of collapse.
Why is air monitoring important in excavations?
✔✔ Excavations can accumulate toxic gases, low oxygen levels, or hazardous fumes that must
be checked before workers enter.
What should workers do if they see signs of a trench wall starting to collapse?
✔✔ Exit immediately and report the hazard to a supervisor before re-entering.
Why is sloping used in excavations?
2
, ✔✔ Sloping cuts back the walls of a trench at an angle to prevent soil from collapsing inward.
Who is responsible for inspecting an excavation site daily?
✔✔ A competent person must inspect the site before each shift and after any changes in
conditions.
Why should ladders or exits be placed in trenches?
✔✔ Workers must have a safe way to exit, and ladders must be placed within 25 feet of workers
in trenches over 4 feet deep.
What is the danger of working in an excavation near underground utilities?
✔✔ Workers can be electrocuted, struck by utility lines, or exposed to hazardous gases if lines
are not properly identified.
How can rain impact excavation safety?
✔✔ Rain can loosen soil, increase water accumulation, and make trench walls more likely to
collapse.
What must be done if a trench is deeper than 20 feet?
3
Questions and Answers | Latest Version
| 2024/2025 | Correct & Verified
What is a trench?
✔✔ A trench is an excavation that is deeper than it is wide, typically less than 15 feet wide.
How can water affect excavation safety?
✔✔ Water can weaken soil, increase the risk of cave-ins, and create hazardous conditions for
workers.
What must be in place before workers enter a trench deeper than 5 feet?
✔✔ A protective system such as sloping, shoring, or a trench box must be used.
Why should excavated soil (spoils) be kept away from the edge of a trench?
✔✔ Keeping spoils at least two feet from the edge prevents them from falling in and adding
pressure that could cause a collapse.
What is a trench shield?
1
,✔✔ A trench shield, also known as a trench box, is a protective structure that prevents workers
from being buried in a collapse.
What is benching in excavation?
✔✔ Benching involves cutting the sides of an excavation into steps to reduce the risk of cave-
ins.
How can vibrations affect excavation safety?
✔✔ Vibrations from heavy equipment, traffic, or machinery can cause soil to shift and increase
the risk of collapse.
Why is air monitoring important in excavations?
✔✔ Excavations can accumulate toxic gases, low oxygen levels, or hazardous fumes that must
be checked before workers enter.
What should workers do if they see signs of a trench wall starting to collapse?
✔✔ Exit immediately and report the hazard to a supervisor before re-entering.
Why is sloping used in excavations?
2
, ✔✔ Sloping cuts back the walls of a trench at an angle to prevent soil from collapsing inward.
Who is responsible for inspecting an excavation site daily?
✔✔ A competent person must inspect the site before each shift and after any changes in
conditions.
Why should ladders or exits be placed in trenches?
✔✔ Workers must have a safe way to exit, and ladders must be placed within 25 feet of workers
in trenches over 4 feet deep.
What is the danger of working in an excavation near underground utilities?
✔✔ Workers can be electrocuted, struck by utility lines, or exposed to hazardous gases if lines
are not properly identified.
How can rain impact excavation safety?
✔✔ Rain can loosen soil, increase water accumulation, and make trench walls more likely to
collapse.
What must be done if a trench is deeper than 20 feet?
3
