29 CFR 1926.651–652: OSHA Excavations

Regulatory citation: 29 CFR 1926 Subpart P, Excavations (1926.650–652)

What Are OSHA's Excavation Standards?

Subpart P of OSHA's construction standards (29 CFR 1926.650–652) covers excavation and trenching work. It requires protective systems to prevent cave-ins, safe means of access and egress, protection from falling loads and hazardous atmospheres, and inspections by a competent person.

Why Trench Safety Matters

A single cubic yard of soil can weigh as much as a small car, and trench collapses can bury and kill workers in seconds. OSHA treats trenching as a high-priority hazard and regularly issues significant penalties for unprotected trenches.

Core Requirements

1. Protective Systems at 5 Feet

Employees in excavations 5 feet deep or more must be protected from cave-ins by an adequate protective system, such as sloping, benching, shoring or a trench shield, unless the excavation is made entirely in stable rock. Shallower trenches may also need protection if a competent person identifies a cave-in hazard.

2. Engineered Design at 20 Feet

Protective systems for excavations deeper than 20 feet must be designed by a registered professional engineer.

3. Safe Access and Egress

A stairway, ladder, ramp or other safe means of egress must be provided in trench excavations 4 feet or deeper, within 25 feet of lateral travel for employees.

4. Keep Spoil and Materials Back

Excavated material and equipment must be kept at least 2 feet from the edge of the excavation, or retained by devices that prevent them from falling in.

5. Test Hazardous Atmospheres

Where oxygen deficiency or hazardous atmospheres could exist in excavations deeper than 4 feet, the atmosphere must be tested before employees enter.

6. Competent Person Inspections

A competent person must inspect excavations, adjacent areas and protective systems daily before work starts, as needed during the shift, and after rainstorms or other events that could increase hazards.

Common Compliance Approaches

Plan Protective Systems Before Digging

Decide on sloping, shoring or shielding based on soil type and depth before excavation begins.

Locate Utilities

Contact 811 and locate underground utilities before digging.

Keep Workers Out of Unprotected Trenches

Never allow entry until protective systems are in place and inspected.

Example: Trench Safety in Practice

A utility contractor digs a 7-foot trench to replace a water main in Type C soil. The competent person selects a trench box rated for the depth and soil, places a ladder within 25 feet of every worker, keeps spoil piles more than 2 feet back and inspects the trench each morning and after an overnight storm before anyone enters.

Related regulations: OSHA Fall Protection, OSHA Confined Spaces, WHS SWMS for high risk construction work.

Note: This summary reflects federal OSHA requirements. States with OSHA-approved State Plans may have additional or different requirements. Always check the current regulation text and any state rules that apply to you.

Frequently Asked Questions

At what depth does OSHA require trench protection?

OSHA requires a protective system for excavations 5 feet deep or more, unless the excavation is entirely in stable rock. A competent person may also require protection in shallower trenches if there's a cave-in hazard.

When is a ladder required in a trench?

OSHA requires a safe means of egress, such as a ladder, stairway or ramp, in trench excavations 4 feet or deeper, located so workers don't have to travel more than 25 feet laterally to reach it.

Who is a competent person for excavations?

A competent person is someone capable of identifying existing and predictable hazards in the excavation and who has authority to take prompt corrective measures. They must be able to classify soil and inspect protective systems.