Access and Egress

OSHA standards require safe access and egress to

all excavations, including ladders, steps, ramps, or

other safe means of exit for employees working in

trench excavations 4 feet (1.22 meters) or deeper.

These devices must be located within 25 feet (7.6

meters) of all workers.

General Trenching and Excavation Rules

• Keep heavy equipment away from trench

edges.

• Identify other sources that might affect trench

stability.

• Keep excavated soil (spoils) and other materials

at least 2 feet (0.6 meters) from trench edges.

• Know where underground utilities are located

before digging.

• Test for atmospheric hazards such as low

oxygen, hazardous fumes and toxic gases

when > 4 feet deep.

• Inspect trenches at the start of each shift.

• Inspect trenches following a rainstorm or other

water intrusion.

• Do not work under suspended or raised loads

and materials.

• Inspect trenches after any occurrence that could

have changed conditions in the trench.

• Ensure that personnel wear high visibility or

other suitable clothing when exposed to

vehicular traffic.

Protective Systems

There are different types of protective systems.

Benching means a method of protecting workers

from cave-ins by excavating the sides of an

Dangers of Trenching and Excavation

Cave-ins pose the greatest risk and are much more

likely than other excavation-related accidents to

result in worker fatalities. Other potential hazards

include falls, falling loads, hazardous atmospheres,

and incidents involving mobile equipment. One

cubic yard of soil can weigh as much as a car. An

unprotected trench is an early grave. Do not enter

an unprotected trench.

Trench Safety Measures

Trenches 5 feet (1.5 meters) deep or greater

require a protective system unless the excavation

is made entirely in stable rock. If less than 5 feet

deep, a competent person may determine that a

protective system is not required.

Trenches 20 feet (6.1 meters) deep or greater

require that the protective system be designed by

a registered professional engineer or be based on

tabulated data prepared and/or approved by a

registered professional engineer in accordance

with 1926.652(b) and (c).

Competent Person

OSHA standards require that employers inspect

trenches daily and as conditions change by a

competent person before worker entry to ensure

elimination of excavation hazards. A competent

person is an individual who is capable of identifying existing and predictable hazards or working

conditions that are hazardous, unsanitary, or

dangerous to workers, soil types and protective

systems required, and who is authorized to take

prompt corrective measures to eliminate these

hazards and conditions.

FactSheet

Trenching and Excavation Safety

Two workers are killed every month in trench collapses.The employer must provide a

workplace free of recognized hazards that may cause serious injury or death. The

employer must comply with the trenching and excavation requirements of 29 CFR

1926.651 and 1926.652 or comparable OSHA-approved state plan requirements.

An excavation is any man-made cut, cavity, trench, or depression in an earth surface

formed by earth removal.

Trench (Trench excavation) means a narrow excavation (in relation to its length) made

below the surface of the ground. In general, the depth is greater than the width, but

the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 meters).
This is one in a series of informational fact sheets highlighting OSHA programs, policies or

standards. It does not impose any new compliance requirements. For a comprehensive list of

compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal

Regulations. This information will be made available to sensory-impaired individuals upon request.

The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.

excavation to form one or a series of horizontal

levels or steps, usually with vertical or nearvertical surfaces between levels. Benching

cannot be done inType C soil.

Sloping involves cutting back the trench wall at

an angle inclined away from the excavation.

Shoring requires installing aluminum hydraulic

or other types of supports to prevent soil movement and cave-ins.

Shielding protects workers by using trench

boxes or other types of supports to prevent soil

cave-ins. Designing a protective system can

be complex because you must consider many

factors: soil classification, depth of cut, water

content of soil, changes caused by weather

or climate, surcharge loads (e.g., spoil, other

materials to be used in the trench) and other

operations in the vicinity.

Additional Information

Visit OSHA’s Safety and Health Topics web page

on trenching and excavation at

www.osha.gov/SLTC/trenchingexcavation/index.html

www.osha.gov/dcsp/statestandard.html

DOC FS-3476 9/2011

U.S. Department of Labor

www.osha.gov (800) 321-OSHA (6742)

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