Caught In-Between Hazards (Trenches)

Hazards include:

Cave-ins, hazardous atmospheres, loss of limbs, injury and death.

Smart Safety Rules:

  • Call 811 several days prior to digging to identify and mark all underground utilities. Examples of underground utilities may include electrical, gas, water, sewer, steam, chemical and telecommunications.
  • Remember that workers outside of a shoring and shielding system are not protected.
  • The angle used for sloping or benching depends on the type of soil present. Soil types are: Solid Rock, Type A, Type B and Type C. Type C is the least stable soil.
  • Ensure that barricades are in place to prevent workers from walking in an area where swinging structures could pin them between a vehicle and an object.


  • Use a ladder, stairway, or properly designed ramp for any trench four feet or deeper at least every 25 lineal feet of the trench
  • Determine the type of soil using at least one visual and one manual test.
  • Use barricades to keep workers out of the area within the swing radius of swinging structures (like cranes) and other solid objects.
  • Properly guard machines and follow lock-out/tag-out procedures to prevent injury.
  • Wear a seatbelt to avoid being thrown from a vehicle and caught between objects.
  • Use protective measures such as sloping, benching, trench boxes or shoring when working in excavations or trenches more than five feet deep.


  • Use benching as a protective measure in Type C soil. Type C is the least stable soil type, and should only be sloped.
  • Underestimate the weight of soil. Some types of soil can weigh around 3,000 pounds for every cubic yard.
  • Dig in an area where you are unsure of the underground utilities.
  • Leave vehicles on when they are not in use to avoid workers from being caught in a piece of equipment or machinery.

Discussion Questions:

  1. What are some protective measures that can be used when working in a trench that is more than five feet deep?
  2. Why should you properly guard machines?
  3. What is some important information you should have prior to digging?
  4. How should you determine the type of soil?