Trenching and Excavation Safety (Part 1)

An excavation is defined as a “man-made cut, cavity, trench, or depression in the earth’s surface formed by earth removal”

A trench is defined as “a narrow underground excavation that is deeper than it is wide, and is no wide than 15 feet”

(Definitions are from OSHA)

Trench and excavation work kills an average of 54 workers each year (these number includes only the reported numbers. Many others may be listed as having other causes of death and not officially be counted as trench related fatalities); injuries number in the hundreds. The costs associated with each trench collapse can reach into the hundreds of thousands of dollars for each incident.

Being buried alive is not a nice way to go, especially considering that most if not all of these injuries and deaths could easily have been avoided by following a few simple safety measures. According to the CDC, up to 95% of injuries and fatalities occurred in trenches where no preventative measures were taken.

Types of accidents

  1. The Spoil Pile Slide – This type of slide is where the dirt that is excavated is piled too close to the trench. When the dirt is piled too high, too close or at a critical angle it can slide back into the trench.
  2. The Shear Wall Collapse – This type of slide occurs when the shear wall breaks off, dumping a large amount of dirt and debris in the trench. This type of collapse usually occurs in clay or layered soil and is most often catastrophic.
  3. The Belly Slough – A pocket of dirt between the top and the bottom of the trench breaks off and slides into the trench
  4. The Lip Slide – Similar to the spoil pile slide, this collapse occurs when the excavated dirt is too close to the top lip of the trench causing pressure. Vibrations from excavating equipment and other machinery can cause a small chunk of dirt to collapse. Because the spoil dirt is resting on this lip, however, the amount of dirt can be much larger than just the amount of dirt from the break.

(Too see a flash animation of each of these types of slides, visit the CDC website at http://www.cdc.gov/niosh/docs/2006-133D/flash/index.html).

2 thoughts on “Trenching and Excavation Safety (Part 1)

  1. Key consideration in Milestones approach to its health and safety policy includes the development of OSHA approved policies and programs. A foreman was awarded the safety suggestion of the month by devising a 24″ corrugated pipe that fit around the excavator hammer to eliminate flying debris.Milestone recognizes the vital importance of health, safety, and welfare of its most valuable resource — the associate. Everyone gets involved with safety at Milestone. The work has not been completed in our cul-de-sac but I know that he will continue to assist and advise me if any problems should arise in regard to my property. If all of your employees are as dedicated and professional on their jobs as him, you have an excellent crew. He has been so nice, courteous and very professional in the way he advised me on when the construction would begin in front of my home. I found Milestone’s superintendent to be a great asset for your company. I live east of the cul-de-sac in Shelby Park Village close to McKay road. We will not sacrifice Safety, Quality, Integrity or the Environment. As of April 13, 2009, the law was amended to give the Board of Elevator Regulations and Department of Public Safety jurisdiction over the installation…

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