Cave In: The Hazards of Excavation and Trenching

excavationExcavation and trenching are among the most hazardous construction operations. Recently, OSHA fined a Chicago company for one willful and one repeated safety violation for not providing cave-in protection or a safe means of exit for employees in a trench more than 6 feet deep. OSHA has specific standards for these activities and, contain requirements for excavation and trenching operations.

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.

 

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