Soil & Protective Systems
This is the least stable soil type according to OSHA.
Type C
This is the leading cause of fatalities in trenching work.
What is cave-ins?
Trenches 4 feet or deeper must have this for workers to enter and exit safely.
Means of egress.
This person must be able to identify existing and predictable hazards.
The competent person.
Where is a shrimps heart?
In its head.
This protective system uses angled sides to prevent cave‑ins.
Sloping
These invisible hazards can accumulate in deep excavations and require atmospheric testing.
What is Hazardous atmospheres?
This must be performed at the start of each shift and after any event that could affect trench stability.
Competent person inspection.
This is the required frequency of trench inspections by the competent person.
Daily by the competent person.
What do bees like that never spoils?
Honey
This protective system uses hydraulic, pneumatic, or timber supports.
What is Sloping
This hazard occurs when heavy equipment operates too close to the trench edge.
What is surcharging or vibration hazard?
Spoil piles stay this minimum distance from the edge when near a trench.
2 feet.
The competent person must remove workers from a trench when this condition is detected.
Hazardous or unsafe conditions.
A snail can sleep for how long during hibernation?
3 Years
This test, often performed with a pocket penetrometer, helps classify soil.
What is manual strength test?
This type of hazard can occur when underground utilities are not located before digging.
What is struck by?
This type of training ensures workers understand trench hazards and protective systems.
Excavation and Trenching safety.
This authority allows the competent person to stop work until hazards are corrected.
Stop work authority.
Three hearts
This type of protective system is a prefabricated structure placed in the trench to protect workers
What is a trench box?
This hazard results from water accumulation or changing weather conditions that weaken trench walls.
What is soil instability?
This emergency measure must be planned for before workers enter a trench.
What is an emergency action or rescue plan?
The competent person must ensure these three elements are in place.
Access/egress, protective systems, and safe working conditions.
Cows