“We’ve made a lot of progress but we’re still a dangerous profession,” says the president of the North American Excavation Shoring Association, Ron Chilton. Described as amongst the most hazardous construction operations (by the Occupational Safety and Health Administration in their Fact Sheet on Trenching and Excavation Safety) excavation and trenching remains a risky process. 

What is an Excavation?

The greatest trench safety hazards are cave-ins, falls, falling loads, hazardous atmospheres, accidents involving mobile equipment and damage to utility lines. This is no surprise when excavation is described as a “man-made cut, trench or cavity in the earth’s surface formed by earth removal.”

Primary hazards

The OSHA data shows that the excavation work fatality rate is 112% higher than that of general construction. Excavation work’s primary hazard is listed, by the agency, as “employee injury from collapse” and states that 1 cubic yard of soil weighs the same as a small car (3000 pounds), easily causing death by suffocation or crushing. 

Unsatisfactory protection precautions exacerbate the problems associated with this deceptively dangerous work and the common perception that shallow trenches are not as dangerous as deep ones is simply not true. 

What can be done?

How can trench hazards be effectively minimized? Cave-ins present the highest risk of all, according to the National Institute for Occupational Health and Safety. These ten precautions can help make your building site safer.


10 Ways to prevent serious trench accidents

  1. A priority precaution to put in place is to never allow workers entry to an unprotected trench. 
  2. Trenches deeper than 5 feet should have a protective system and trenches more than 20 feet should have a professionally designed protective system. 
  3. Sloping (cutting the trench wall at an angle), shoring (support installation) and shielding (use of supports to protect workers) are all reliable and trustworthy methods of protecting the trench and ensuring your workers’ safety. 
  4. Make sure that all heavy equipment is kept away from the trench edges. 
  5. Ask a competent employee to inspect the trench daily and again after rain, before allowing workers access, and ensure safe egress from the excavations through easy availability of steps, ladders or ramps. 
  6. To minimise “struck-by” incidents, have your workers wear high-visibility clothing; select a spotter or flagger to supervise off-loading of equipment and materials and have workers stand back when unloading.
  7. Install barriers and safety signage to prevent falls and falling equipment. OSHA guidelines require materials to be stored a minimum of two feet from the excavation edge.
  8. Damage done to utility lines whilst excavating could cause dangerous gas leaks and electrocutions. Before beginning your work, call your local 811 agency and ask them to mark their lines on site.
  9. When working near old landfills, be cautious of methane gas or hydrogen sulphide inhalation.
  10. Depleted oxygen levels are possible at the bottom of deep trenches and respiratory protection equipment may be necessary. Get an expert to test the air quality, if you have any concerns.

Simple precautions and proper preparations can protect your workers, saving them from injury and possible loss of life and prevent delays in project completion and lowering of worker morale. 


Tip: If you have a business with employees involving in such risks, Workers’ Compensation Insurance must be crafted for both your business and your employees. Aside from it is required by law in most states, here’s an article discussing how your business could avoid penalties and losses when you have this policy in place.