Issues
Trench collapses, or cave-ins, pose the greatest risk to workers’ lives. When performed safely, trenching operations can reduce worker exposure to other potential hazards, including falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment.
- Soil weighs between 90 and 140 pounds per cubic foot. Therefore, one cubic yard (3 ft. × 3 ft. × 3 ft.) can weigh as much as a small pickup truck. If a person is buried, there is little chance of survival.
- Many factors can affect soil stability, including the type of soil, water, and vibration. Soils saturated with water and previously disturbed soils are very dangerous to work in or around. However, don’t be fooled—even hard soil and rock that appear stable can cave in.
- About half of the people killed each year in trenches die trying to rescue someone else who has been buried by a cave-in. Call 911 for help. Do not attempt a rescue unless you have been properly trained in trench rescue techniques.
- Other hazards include falling objects, hazardous atmospheres, and exposure to mobile equipment and traffic.
- Remember, if you are buried by a cave-in, your chance of survival is very low. Therefore, always ensure the trench walls are sloped, shored, or shielded with a trench box and that the trench is safe before you enter.
Sources of Hazards
- Lack of pre-planning and site visits.
- Improper protective systems.
- No assigned Competent Person.
- Failure to follow engineer’s designs or manufacturer’s requirements.
- Working under suspended loads or failing to keep material from falling into the work area.
- Lack of training.
Regulations
29 CFR 1926.651(a) – Surface Encumbrances
All surface encumbrances that are located so as to create a hazard to employees shall be removed or supported, as necessary, to safeguard employees.
29 CFR 1926.652(b) – Design of Sloping and Benching Systems
The slopes and configurations of sloping and benching systems shall be selected and constructed by the employer or the employer’s designee and shall be in accordance with the requirements of paragraph (b)(1), paragraph (b)(2), paragraph (b)(3), or paragraph (b)(4).
29 CFR 1926.652(c)(2)(iii) – Manufacturer’s Specifications
Manufacturer’s specifications, recommendations, limitations, and written approval to deviate from those specifications, recommendations, and limitations shall be maintained at the jobsite during construction of the protective system. After construction, this information may be stored off-site, but a copy shall be made available to the Secretary upon request.
29 CFR 1926.652(b)(3)(iii) – Tabulated Data
At least one copy of the tabulated data identifying the registered professional engineer who approved the data shall be maintained at the jobsite during construction of the protective system. After construction, the data may be stored off-site, but a copy shall be made available to the Secretary upon request.
29 CFR 1926.651(f) – Warning System for Mobile Equipment
When mobile equipment is operated adjacent to an excavation, or when such equipment is required to approach the edge of an excavation and the operator does not have a clear and direct view of the edge, a warning system shall be utilized, such as barricades, hand or mechanical signals, or stop logs. If possible, the grade should slope away from the excavation.
5-4-3-2-1 Rules for Excavations
5. Protective Systems
29 CFR 1926.652(a)–(c)
Each employee in a trench or excavation shall be protected from cave-ins by an adequate protective system, except when excavations are less than 5 feet in depth.
4. Access and Egress
29 CFR 1926.651(c)
Provide employees with a means of access and egress when the trench is 4 feet or deeper. Ensure the means of access and egress is located within 25 feet of lateral travel for all employees working in the excavation.
3. Ladders
29 CFR 1926.651(c)
Ladders must be secured, extend a minimum of 3 rungs (36 inches) above the landing, and be tied off. If no ladder is used, employees must be able to enter and exit the trench or excavation while maintaining three points of contact.
2. Spoil Piles and Equipment
29 CFR 1926.651(j)
Provide protection from loose rock, soil, tools, and other items that may fall or roll into the excavation. Maintain a clear 2-foot area at the excavation edges.
1. Competent Person
29 CFR 1926.650 – Scope and Definitions
Each trench or excavation must have a minimum of one Competent Person.
Example Incidents: The Facts
In the United States, trenching kills an average of 40 workers every year. Workers can suffer death or serious injury within minutes of being caught in a trench cave-in.
- January 3, 2025: A miner at Borger Pit in Hutchinson County, Texas, died in a trench collapse.
- March 3, 2025: Two workers died in a trench collapse in Maryland.
The Basics Expanded
- Pre-planning is essential, including a site inspection before digging.
- OSHA requires that protective systems for excavations and trenches deeper than 20 feet be designed by a registered professional engineer.
- If the trench parameters or site conditions are not covered by OSHA standards (Appendices) or manufacturer’s tabulated data (MTD), a site-specific engineered design is necessary. This applies to both shoring and sloping/benching systems.
- Protective systems (e.g., sloping, benching, shoring, or shielding) are required where the soil or rock is unstable or prone to collapse and could cause injury, or when a trench or excavation is deeper than 4 feet. Benching cannot be used in Type C soil.
- Provide adequate access and egress. Never climb, or allow anyone to climb, the sides of an excavation or trench.
- Management control of risk through supervision and control of work. Allow no more personnel in the trench or excavation than are absolutely necessary to perform the task at hand. Minimize access to the excavation.
- Do not work under suspended or raised loads or materials.
- Provide daily and ongoing inspections.
- Have a rescue plan. A written plan is recommended for deep excavations and is required for trenches over 20 feet deep.
- Wear high-visibility or other suitable clothing when exposed to vehicular traffic inside the excavation or at the edges of trenches and excavations.
- Hard barricades are the most effective protective system at excavation and trench edges.
Competent Person Responsibilities
a. Ensure proposed excavations have been marked for underground utility locating and contact the utility locating service.
b. Know and understand utility locating services and their markings.
c. Classify the soil type.
d. Prescribe and ensure proper installation of protective systems.
e. Identify and correct all hazards, including those associated with confined spaces.
f. Ensure employees are protected from spoil piles, surface encumbrances, and all other potential hazards surrounding the excavation.
g. Ensure adequate access and egress.
h. Ensure the excavation is properly barricaded and protected from the public.
i. Ensure atmospheric monitoring is performed when necessary.
j. Perform daily trenching and excavation inspections prior to the start of work, as needed throughout the day, and after rain or other events.
k. Evacuate exposed employees from an excavation or trench if there is evidence of a situation that could result in a possible cave-in, indications of protective system failure, or hazardous atmospheres. All employees shall be removed from the hazardous area until the necessary precautions have been taken to ensure their safety and eliminate hazardous conditions.
What You Need to Know
- Planning and physical site inspections are required before digging and must continue daily throughout operations.
- Who is your designated Competent Person on site? Do they understand the scope of their responsibilities listed in Number 12 in the previous section?
- Have all surface obstructions within the excavation or trench been removed, supported, or included in a written removal plan before digging begins?
- Is all required tabulated data for protective systems (sloping, benching, shoring, or shielding) readily available on site? This can be as simple as knowing where the OSHA tabulated data is located (utilizing 29 CFR 1926.652(c)) or having access to the applicable engineered or manufacturer’s requirements.
Important Do’s to Keep in Mind About Trenches and Excavations
- Do participate in, or require, pre-planning before excavation begins.
- Do require a Competent Person to perform daily and ongoing evaluations, and ensure all workers know who that person is.
- Do enter only trenches or excavations that have been properly sloped, shored, or shielded.
- Do require that tabulated data for support systems be on site or readily available.
- Do require appropriate access, egress, equipment, and procedures.
- Do check regularly for hazardous atmospheres and oxygen levels in the trench.
- Do use a ladder or ramp to enter and exit the trench. Place the ladder inside the protective system.
- Do ensure spoil piles and materials are far enough away to prevent struck-by hazards.
- Do stay out from under suspended or raised loads.
- Do remain mentally focused the entire time you are in a trench or excavation.
- Do prepare a rescue plan.
Important Don’ts to Keep in Mind About Trenches and Excavations
- Don’t adopt a “get it done” attitude and just dig in and go.
- Don’t use support systems without understanding the applicable OSHA information, engineered design information, or manufacturer’s utilization data.
- Don’t simply climb into a trench or slide down the sides of an excavation.
- Don’t climb on shoring or trench shields. Never ride in equipment buckets or on crane hooks.
- Don’t store anything close to a trench or excavation that could fall into the work area.
- Occupational Safety and Health Administration. Trenching and Excavation Safety. U.S. Department of Labor, https://www.osha.gov/trenching-excavation. Accessed 30 June 2026.
- Occupational Safety and Health Administration. 29 CFR 1926 Subpart P—Excavations. U.S. Department of Labor, https://www.osha.gov/laws-regs/regulations/standardnumber/1926/subpartP. Accessed 30 June 2026.
- Occupational Safety and Health Administration. 29 CFR 1926.651—Specific Excavation Requirements. U.S. Department of Labor, https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.651. Accessed 30 June 2026.
- Occupational Safety and Health Administration. 29 CFR 1926.652—Requirements for Protective Systems. U.S. Department of Labor, https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.652. Accessed 30 June 2026.
- Occupational Safety and Health Administration. Protect Workers in Trenches. U.S. Department of Labor, https://www.osha.gov/sites/default/files/publications/trenching-factsheet.pdf. Accessed 30 June 2026.
