By Bruce Loughner, CSP, Technical Safety Advisor
A trench cave-in can trap you within seconds and kill you within minutes. One excavator buck load, or one cubic yard of soil, weighs about 3,000 pounds. If the walls collapse and you’re buried, you could suffocate in less than three minutes. The weight of the soil causes serious internal injuries, and survivors have talked about the inability to move while being trapped in a cave-in.
In addition to the cave-in risk, there are other hazards in trenches and excavation work, including buried power lines, explosive gases, lack of oxygen, and toxic fumes. Appropriate planning can counter these risks and reduce the chance something will go wrong during a job. It’s never ‘too expensive’ or ‘too slow’ when providing appropriate safeguards.
You must be protected from a cave-in if you work in an excavation five feet deep or more, or if a competent person determines that there’s a potential for a cave-in. The competent person must conduct daily inspections before the work begins and be knowledgeable about the types of soils, protective systems, and signs of instability, such as cracks in the soil. Inspections are also required after heavy rain, blasting, heavy vibrations, or other conditions and activities that may increase the risk of a cave-in. The competent person must have authority to immediately correct and safeguard for hazards.
Employees require training to identify excavation hazards, plan for emergencies, and have a team ready to respond. See OAC 4123:1-3-13 for the Trenches and Excavations Rule. Here are some hazards and other considerations for conducting trenching operations:
- Debris near the excavation site that could fall in on workers.
- Employee access and egress in and out of the excavation.
- Falling into a trench. (Fall protection is needed for depths of six feet and over).
- Overhead power lines and underground utility lines. (Call 811 from anywhere in Ohio for help locating underground utility lines).
- Atmospheric hazards in the excavation.
- Water near the excavation site.
- Soil stability at the excavation site.
- Stability of structures adjacent to the excavation site.
- Vehicles and other mobile equipment that will operate near the excavation.
- Weather conditions.
Trench safety resources
The 2022 Trench Safety Stand Down, presented by the National Utility Contractors Association (NUCA), takes place June 20-24, 2022 during June’s Trench Safety Month. NUCA’s website contains all the information you will need to conduct a successful Trench Safety Stand Down event. This year’s event will occur at hundreds of jobsites across the nation, reaching tens of thousands of workers.
In addition to participating in the Trench Safety Stand Down, visit BWC’s Trench Safety Ohio subsite at any time to access trench safety resources and training, and details about BWC’s Trench Safety Grant. You can also view our Micro Training Safety Series videos about trench safety.