Trenches & Excavations Training Guide

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Labor Occupational Health Program

Summary Statement

A guided discussion through hazards of trenches and excavations, a set of questions to use for discussion and a sign-off form. Part of a collection. Click on the 'collection' button to access the other items.

These tailgate/toolbox talks were developed for use under California OSHA regulations. The complete set is available from the Labor Occupational Health Program at UC Berkeley. For ordering information, visit the website ( The American Conference of Government Industrial Hygienists (ACGIH) has adapted these talks to apply to federal OSHA regulations. To contact ACGIH, visit its web site (

    Before you begin the meeting

  • Does this topic relate to the work the crew is doing? If not, choose another topic.
  • Did you read this Training Guide and fill in the blanks where thePencil Icon appears? (To find the information you need, look over the Safety Walkaround Checklist for this topic.)

Begin: This meeting is about working safely around trenches and excavations. A lot of people think if there's ever a cave-in, they'll just outrun it. But that could be the biggest mistake you'll ever make. You can't outrun them. Between 50 and 100 workers die each year in the U.S. from .cave-ins and other trenching accidents. Never enter an unsafe trench or excavation!

You or a crew member may want to add a personal story about trenches or excavations.

Next, discuss with the crew where you will be excavating at this particular job site:

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After each question, give the crew time to suggest possible answers. Use the information following each question to add points that no one mentions.

1. According to Cal/OSHA, excavations over five feet deep require a permit if workers will be entering them. We must have a competent person in charge. What does that person do?

  • Determines the type of soil, and decides what kind of cave-in protection is needed.
  • Inspects the operation daily and after every rainstorm, snowstorm, or earthquake.
  • Checks and corrects any hazards.
  • Determines if there are hazardous fumes or vapors in the excavation, and if there is enough oxygen.
  • Can shut down the operation until it is safe.
  • Must always be on the when anyone is working in or around the excavation.
Pencil Icon The "competent person" for this job is: ________________________________.

2. When does a trench or excavation need shoring, sloping, benching, shielding, or other protection from cave-ins?

  • If five feet deep or more.
  • When less than five feet deep, similar protection may be needed if the competent person has not yet inspected the excavation and determined it is safe from cave-ins.

3. An excavation can cave in if weakened by rain, snow, or other water. What precautions do we have to take in wet conditions?

  • As a general rule, don't work in accumulated water.
  • The competent person must re-inspect after each rainstorm or snowstorm.

4. What do you need to know about utility lines when excavating?

  • The area should be marked by the Underground Service Alert (USA) system to show location of underground utility lines.
  • Make sure you're not interfering with any kind of utility--underground, overhead, or on the surface. Watch out for electrical, gas, telephone, water, and sewer lines.
  • Keep all equipment at least six feet from any electric power line (more distance for very high voltage). Remember that electricity can arc.
5. Where should spoil go? How far back from the edge.
  • Keep it at least two feet from the edge. If you can't, use retaining devices adequate to prevent it from falling into the excavation.
  • The same applies to all tools, equipment, and other materials. Keep them at least two feet from the edge, or use retaining devices.

6. How do you get in and out of a trench or excavation safely? How do you cross over safely?

  • If the excavation is over four feet deep, there should be designated access points within 25 feet of any worker in the excavation.
  • If equipment or people cross over a trench deeper then 6 feet or wider than 30 inches, there must be a walkway with standard guardrails.
  • Trenches and excavations in remote areas should be barricaded.

7. When do you need a lookout standing by?

  • Always.

8. What precautions should you take if a trench or excavation is classified as a "confined space"?

  • Don't go in until the competent person checks out the air. There may be toxic vapors or fumes, insufficient oxygen, or both.
  • Follow directions from the competent person. You'll be told what special precautions to take.
Pencil Icon Confined spaces on this site:____________________________________


Explain: Most of the safety measures we've talked about are required by Cal/OSHA. We have to take these precautions -- it's the law. I have a Checklist of the Cal/OSHA regulations on trenches and excavations. If you'd like to know more, see me after the meeting.


(Only if applicable.) Besides the Cal/OSHA regulations, we have some additional company rules about trenches and excavations.

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Discuss company rules: ___________________________________________



Ask: Do you have any other concerns about trenches or excavations? Do you see any problems on our job? (Let the steward answer first, if there is one.)

What about other jobs you've worked on? Have you had any experience with trenches or excavations that might help us work safer on this job?

Sign Off Form

Date Prepared:_________________________ By:____________________
Project Name/No.______________________ Location:_______________
Printed Name