The Truth Behind Trench and Excavation Safety

Trench SafetyBefore jumping into this article, take a look at a few important facts about working in or around trenches and excavations:

  • Working in trenches and excavations is one of the most hazardous types of work.
  • As many as 400 workers have been killed yearly in trenches and excavations across the United States.
  • Several thousand more workers are seriously injured.
  • Most of the trenches and excavations in which workers are injured or killed are relatively shallow (5 to 15 ft deep).
  • Many of the workers have not had excavation safety training.

The Weight of Soil
Many people don’t appreciate the weight of soil. One cubic foot of soil weighs between 90 and 140 lbs. Just one cubic yard of soil (27 cubic ft), weighs between 2,430 and 3,780 lbs. The human body isn’t designed to accept the trauma of having that much weight fall on it.

The deaths and injuries result from suffocation, crushing, drowning, loss of circulation and objects rolling or falling into the trench or excavation.

Cave-ins are a simple matter of physics. Think about it: Before we excavate, all the physical forces of nature are in balance. There is equal pressure in all directions in the soil. But once we start excavating, we create a void — an empty space. The earth will want to “heal itself” — except in stable rock, which is extremely rare — by caving-in. (See figures 1-3 below.)

The end result is that when trench walls cave in, and workers are not properly protected (by sloping, shoring or shielding), they will most likely be crushed. They don’t stand a chance. And there is a mistaken belief that workers have to be totally covered up to die. The reality is that workers die after being just partially buried.
OSHA’s 29 CFR, Part 1926, Subpart P — Excavations (hereafter referred to as “Subpart P”) was specifically developed to address the hazards associated with trenches and excavations. OSHA’s definition of a “cave-in” has two parts:

  1. The separation of a mass of soil or rock material from the side of an excavation, or the loss of soil from under a trench shield or support system, and
  2. Its sudden movement into the excavation, either by falling or sliding, in sufficient quantity so that it could entrap, bury or otherwise injure and immobilize a person.

There are many negative results of a cave-in (aside from the obvious), particularly if workers are seriously injured or killed. Of course, there is a significant impact on the injured workers and their families. There can also be large direct and indirect expenses associated with the cave-in for the employer. There are OSHA citations, which are sometimes hundreds of thousands of dollars. And, finally, criminal charges can be filed.

Trench Safety

Trench Safety

Trench Safety

What Is the True Cost of an Accident Involving Injury or Death?
At least two very real losses are usually clearly felt by contractors and utilities when there is an accident involving injury or death on a jobsite. Below are examples of such losses:

Monetary Losses

  • Loss of skilled, experienced workers.
  • Loss of profit from such workers.
  • Loss of production.
  • Training expense for new personnel to take over for the injured personnel.
  • Re-training expense for the injured worker to handle another job.
  • Payment of compensation.
  • Legal costs.
  • Awards paid out for lawsuits.
  • Settlement awards.
  • Increased workman’s compensation premiums.
  • Increased general liability insurance premiums.
  • Federal OSHA fines for non-compliance.
  • State and local fines for non-compliance.

Time Losses

  • Time investigating the cause of the accident.
  • Time processing the accident reports.
  • Time preparing personnel reports.
  • Time attending depositions, hearings and trials.
  • Time for additional training and supervision of new employees.
  • Time for mental stress and fatigue due to concern for the worker’s family and friends.

And even with accidents that do not involve injury or death, the out-of-pocket costs for a contractor or utility can be significant:

  • Existing utilities and nearby structures can be damaged.
  • Time and money are required to re-excavate the trench to start all over again.

Why Is Safety so Important in Trenches and Excavations?
Stressing the importance of trench and excavation safety can never be underrated. No one wants a co-worker or an employee injured or killed on the job, so taking the proper precautions before performing this type of work is key. By establishing effective training and having the correct equipment on board, employees will feel a company values their safety. Potential employees will also want to work for a company that protects its workers. In addition to boosting morale, a dedication to safety helps better control direct and indirect costs, due to less accidents and lost time. Most importantly, maintaining a safe work environment is the law! Employers have a legal obligation to provide a safe workplace for all of their employees. Therefore, there’s no time to lose. Be sure your crews know the dangers of trench and excavation work and that they have the right tools to ensure they are safe on the job.

David V. Dow is Co-founder and Vice President of TrenchSafety and Supply Inc., which supplies excavation safety products and services to construction, excavation and utility companies throughout the Mid-South. For more information, visit