Here is a risk assessment for excavation work:

1. Cave-ins: This is a major hazard in excavation work.

   • Risk: Could lead to serious injury or death. [1]
   • Control Measures:
     • Implement adequate protective systems such as sloping, benching, shoring, or shielding 2, 6, 14.
     • Ensure a competent person inspects the excavation daily and after any hazard-increasing event 6, 15.
     • Remove employees from the hazardous area if a potential cave-in is identified until safety precautions are taken [1].

2. Underground Utilities: Striking underground utilities can cause electrocution, explosions, or flooding 5, 12.

   • Risk: Electrocution, burns, explosions, property damage.
   • Control Measures:
     • Determine the estimated location of utilities before excavating 5, 12.
     • Contact utility companies to establish the exact location of underground installations [2].
     • Use safe digging practices, including hand digging when near utilities [3].
     • Protect, support, or remove underground installations as necessary 5, 12.

3. Water Accumulation: Accumulated water can lead to cave-ins, instability, and drowning 2, 13.

   • Risk: Drowning, cave-in, trench collapse.
   • Control Measures:
     • Prevent water accumulation using water removal equipment, diversion ditches, or dikes 2, 13.
     • If water is present, use support or shield systems, or safety harnesses and lifelines 2, 13.
     • A competent person should monitor water removal equipment 2, 13.

4. Falling Loads and Equipment: Workers can be struck by falling loads or equipment operating near the excavation 7, 18.

   • Risk: Injury from falling objects or equipment.
   • Control Measures:
     • Do not allow employees under loads handled by lifting or digging equipment 7, 18.
     • Use warning systems for mobile equipment near the excavation edge 7, 18.
     • Keep materials and equipment at least 2 feet from the edge of excavations or use retaining devices [1].

5. Hazardous Atmospheres: Excavations, especially in landfills or near stored substances, may contain hazardous atmospheres 7, 18.

   • Risk: Exposure to harmful contaminants, oxygen deficiency, explosion.
   • Control Measures:
     • Test the atmosphere before entry, especially in excavations deeper than 4 feet 7, 18.
     • Provide proper respiratory protection or ventilation 13, 18.
     • Ensure adequate precautions to prevent exposure to hazardous atmospheres [4].

6. Falls: Workers can fall into excavations [5].

   • Risk: Injury from falls.
   • Control Measures:
     • Provide walkways with guardrails where employees cross over excavations, especially if the walkway is 6 feet or more above lower levels 6, 15.
     • Use stairways, ladders, or ramps for safe egress, ensuring no more than 25 feet of lateral travel in trenches 4 feet or deeper 7, 18.

7. Falling Rock or Soil: Loose rock or soil can fall from the excavation face [1].

   • Risk: Injury from falling debris.
   • Control Measures:
     • Scale the excavation face to remove loose material 6, 8.
     • Install protective barricades to contain falling material [1].

8. Confined Space Hazards: Excavations can sometimes present confined space hazards [6].

   • Risk: Asphyxiation, exposure to toxic substances.
   • Control Measures:
     • Identify potential confined space hazards [6].
     • Implement confined space entry procedures, including testing, ventilation, and rescue plans [6].

9. Stability of Adjacent Structures: Excavation can endanger the stability of nearby structures [7].

   • Risk: Collapse of adjacent structures.
   • Control Measures:
     • Provide support systems like shoring, bracing, or underpinning [7].
     • Ensure a registered professional engineer approves work that could affect structural stability [1].

10. Traffic Hazards: Workers may be exposed to vehicular traffic 7, 18.

    • Risk: Struck by vehicles.
    • Control Measures:
      • Provide and require the use of warning vests or high-visibility garments 7, 18.
      • Implement traffic control measures 7, 18.

Monitoring and Review:

• Regularly inspect the excavation, adjacent areas, and protective systems 6, 15.
• Review the risk assessment periodically and update as necessary.
• Ensure a competent person is always on site to monitor conditions and implement corrective actions 6, 9.