Here is a risk assessment for excavation work:

1. Hazard Identification

• Cave-ins: The primary hazard in excavation work is cave-ins, which can cause serious injury or death to workers [1]. Factors contributing to cave-ins include soil type, water content, vibration, and surcharge loads 20, 17.
• Underground Utilities: Striking underground utilities such as gas, electric, or communication lines can result in electrocution, explosion, or service disruption 5, 8, 12.
• Falling Loads and Equipment: Workers can be struck by falling loads from lifting or digging equipment or by equipment operating too close to the excavation edge 7, 18.
• Hazardous Atmospheres: Excavations, especially in landfills or areas with nearby hazardous substance storage, may contain hazardous atmospheres such as oxygen deficiency or flammable gases 7, 13, 18.
• Water Accumulation: Accumulated water in excavations can lead to instability and collapse, as well as create a drowning hazard 2, 13.
• Falls: Workers can fall into excavations, especially if walkways are not properly guarded 6, 15.
• Falling Objects: Loose rock or soil can fall from the excavation face, and equipment or materials can roll into the excavation [1].
• Adjacent Structures: Excavation work can compromise the stability of nearby buildings or walls [2].

2. Risk Assessment

The risk associated with each hazard depends on factors such as the depth and width of the excavation, soil conditions, proximity to utilities and structures, weather conditions, and worker training and experience. Cave-ins generally pose the highest risk due to their potential for serious injury or death.

3. Control Measures

• Elimination/Substitution: Where possible, eliminate the need for workers to enter the excavation by using remote-controlled equipment or alternative methods.
• Engineering Controls:
  • Protective Systems: Implement appropriate protective systems such as sloping, benching, shoring, or shielding to prevent cave-ins 2, 6, 14. The choice of system depends on soil type, excavation depth, and other factors 20, 17.
  • Water Removal: Use water removal equipment to prevent water accumulation in the excavation 2, 13.
  • Shoring/Underpinning: Provide shoring, bracing, or underpinning to support adjacent structures endangered by the excavation [2].
  • Guardrails: Install guardrails around walkways crossing excavations that are 6 feet (1.8 m) or more above lower levels 6, 15.
• Administrative Controls:
  • Competent Person: Designate a competent person to inspect excavations daily for hazards and to ensure that protective systems are in place and effective 6, 15. The competent person should be able to identify existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them [3].
  • Utility Location: Contact utility companies to locate and mark underground installations before excavation begins 5, 8, 12.
  • Atmospheric Testing: Test the atmosphere in excavations deeper than 4 feet (1.22 m) for oxygen deficiency and hazardous substances before entry 7, 18.
  • Warning Systems: Use barricades, hand signals, or stop logs when mobile equipment is operated near the edge of an excavation 7, 18.
  • Safe Access/Egress: Provide a safe means of access and egress, such as a ladder, stairway, or ramp, located within 25 feet (7.62 m) of lateral travel 7, 18.
  • Spoil Pile Placement: Keep excavated material at least 2 feet (.61 m) away from the edge of excavations [1].
• Personal Protective Equipment (PPE):
  • Hard Hats: Require all workers in the excavation area to wear hard hats to protect against falling objects.
  • High-Visibility Clothing: Provide and require workers exposed to vehicular traffic to wear high-visibility vests or clothing 7, 18.
  • Respiratory Protection: Provide appropriate respiratory protection when hazardous atmospheres are present 13, 18.

4. Monitoring and Review

• Conduct regular inspections of excavations, protective systems, and adjacent areas by a competent person 6, 15.
• Monitor water removal equipment and operations 2, 13.
• Reclassify soil if conditions change [4].
• Review the risk assessment and control measures whenever there are changes in site conditions, equipment, or work practices.

5. Specific, Actionable Recommendations

• Develop a written excavation safety plan that includes hazard identification, risk assessment, and control measures.
• Train all workers on excavation hazards and safe work practices.
• Ensure that a competent person is on site during all excavation activities.
• Implement a permit-to-work system for excavations deeper than 4 feet (1.22 m).
• Conduct regular safety meetings to discuss excavation hazards and reinforce safe work practices.