Protective Systems: Trench Boxes and Shoring Safety

• Cave-ins from improper protective system use
• Workers outside the protected area
• Trench boxes or shoring used beyond design limits
• Improper installation, movement, or removal
• Changing soil, water, or surcharge conditions
• Unsafe access into or out of protected excavations

Protective systems such as trench boxes and shoring are used to protect workers from cave-ins, but they only work when they are selected, installed, and used correctly. Having a box or shoring on site does not automatically make the excavation safe.

A competent person must evaluate the excavation, soil conditions, depth, water, surcharge loads, and other hazards to determine what protective system is needed.

Workers must stay within the protected area. Standing outside the trench box, working beyond the end of the shield, or entering unprotected sections of the excavation can expose workers to collapse hazards.

Trench boxes and shoring systems should be used according to their design, tabulated data, or manufacturer’s requirements. Depth limits, spreader placement, stacking, bedding, and allowed use conditions must be respected.

Moving trench boxes creates hazards. Workers should stay clear while boxes are being lifted, dragged, pushed, or repositioned. No one should ride the box or stand in pinch points during movement.

Shoring removal and adjustment can also change trench stability. Soil may move when supports are changed, especially in wet, loose, previously disturbed, or unstable ground.

Access and egress must still be provided. Workers should have safe ladders, ramps, or other approved access inside the protected work area.

Protective systems are a critical control, but they require constant attention. If soil, water, depth, equipment placement, or work location changes, the system should be reassessed before workers continue.

• Use protective systems selected by a competent person.
• Stay inside the protected area.
• Follow manufacturer or tabulated data requirements.
• Keep workers clear when moving trench boxes.
• Reassess protection when soil or water conditions change.
• Provide safe access and egress inside the protected area.
• Stop work if the protective system no longer matches the excavation.

• Has a competent person evaluated the excavation?
• Are workers staying inside the protected area?
• Is the trench box or shoring being used within its limits?
• Are workers clear during movement or adjustment?
• Have soil, water, depth, or surcharge conditions changed?