Excavation and trenching are among the most hazardous construction operations. Recently, OSHA fined a large construction company after discovering employees working in an unprotected 10-foot deep excavation at a suburban New Jersey high school, in violation of federal safety and health laws.
An excavation and a trench are defined slightly differently by the agency: an excavation is any man-made cut, cavity, trench, or depression formed by earth removal. A trench is defined as a narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth of a trench is greater than its width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m).
Cave-ins pose the greatest risk and are more likely than some other excavation-related incidents to result in worker fatalities. According to OSHA, one cubic yard of soil can weigh as much as a car. Employers must ensure that workers enter trenches only after adequate protections are in place to address cave-in hazards. Other potential hazards associated with trenching work include falling loads, hazardous atmospheres, and hazards from mobile equipment.
OSHA generally requires that employers protect workers from cave-ins by:
- Sloping and benching the sides of the excavation;
- Supporting the sides of the excavation; this could include placing a shield between the side of the excavation and the work area.
- OSHA generally requires that employers protect workers from cave-ins by:
- Sloping and benching the sides of the excavation;
- Supporting the sides of the excavation; or
- Placing a shield between the side of the excavation and the work area.
Safe practices for working with excavation and trenches include:
- Know where underground utilities are located before digging.
- Keep excavated soil (spoils) and other materials at least 2 feet (0.61 meters) from trench edges.
- Keep heavy equipment away from trench edges.
- Test for atmospheric hazards such as low oxygen, hazardous fumes, and toxic gases when workers are more than 4 feet deep.
- Inspect trenches at the start of each shift.
- Inspect trenches after any occurrence that could have changed conditions in the trench, including rainstorms.
- Do not work under suspended or raised loads and materials.
- Ensure that personnel wear high-visibility or other suitable clothing when exposed to vehicular traffic.
For more construction safety information, contact our offices at Diversified Safety Services.
