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General Orientation

Rev. November 10, 2020

Buried Services

Hazards involving excavations, in particular trenches, can lead to serious incidents involving workers at construction sites.

Buried Services Policy

(Document Web Link)

Excavation Hazards

Workers can be critically injured or die in cave-ins. Many cave-ins occur on small jobs of short duration, such as water, gas, electrical and sewer line connections.


More hazards

  1. falls into trenches or excavations

  2. tripping over equipment, debris and spoil

  3. excavated material or other objects falling on workers

  4. exposure to underground services or overhead electrical cables

  5. unstable adjacent structures

  6. mishandled or poorly placed materials

  7. hazardous atmosphere (noxious gases/lack of oxygen)

  8. toxic, irritating or flammable and explosive gases

  9. incidents involving vehicles and other mobile equipment


Plan before you dig

  1. remove debris and excavated soil near excavation site

  2. arrange to protect workers from falling into excavation

  3. plan for removing water in excavation

  4. identify and locate overhead power lines and underground services

  5. know soil types and what sloping, shoring or pre-fabricated, hydraulic or engineer systems are required

  6. obtain utility locations before digging


Reasonable precautions for Supervisors

  1. determine how workers will enter and exit excavation

  2. know in advance what excavation equipment and tools are needed

  3. consider possibility of environmental hazards (rain) in excavation

  4. be aware of nearby vehicles and mobile equipment causing soil to vibrate

  5. provide awareness training to workers


Mark and locate utilities

  1. ensure all gas, electrical and other services are located or marked in or near the area to be excavated. If a service poses a hazard, it must be shut off and disconnected before the excavation activity begins. If a potentially hazardous service cannot be disconnected, the service owner must be asked to supervise the service’s uncovering during the excavation.

  2. Call Ontario OneCALL 800-400-2255 with Contractor ID 230380

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