Cave-In Warning Signs

Trench walls often give small warnings before they collapse, but sometimes only seconds before. A cubic yard of soil can weigh about as much as a car. Every worker near a trench should know the signs and get out the moment they see one.

• Construction
• All workers

Warning signs

• Tension cracks in the ground running along the trench edge, often a few feet back
• Bulging or bowing of the trench wall
• Spalling or sloughing: chunks or sheets of soil falling from the wall
• Small amounts of soil trickling or rolling into the trench
• Water seeping from the walls, or bubbling up from the bottom
• Heaving: the trench bottom pushing up
• Sinking or settling ground near the edge
• Movement or noise from shoring or a trench box shifting
• Recent rain, thawing, or new vibration from equipment or traffic

What to do

1. Get out immediately using the nearest ladder or exit.
2. Warn everyone in and around the trench.
3. Keep people and equipment back from the edge.
4. Tell the competent person, who must reinspect and fix the problem before anyone goes back in.

If there is a cave-in

• Call 911 immediately and ask for a trench rescue team.
• Don’t jump in to dig; secondary collapses kill would-be rescuers.
• Shut down nearby equipment to reduce vibration, and keep people back from the edge.
• See Trench Emergencies.

Who watches for these signs

A competent person inspects the excavation daily before work, as needed during the shift, and after rain or other events. But every worker has the right and responsibility to stop and get out when they see danger. See Stop-Work Authority.

Last updated: October 2, 2026