How to Prevent Death from Trench Collapse

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Updated Jun 8, 2023
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Following industry safety practices can prevent deaths and injuries in trenches.
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When 1 cubic yard of dirt can weigh as much as 3,000 pounds, or as much as a small pickup truck, and it’s caving in on a worker, it often leads to fatal crushing and suffocation.

There is no time for a worker to react to these sudden collapses. The rescues – which often turn into body recovery missions – are difficult, painstaking and can take hours. Meanwhile, family, friends and coworkers face the heartbreaking frustration of helplessly watching and waiting.

Here’s a guide to preventing that from happening on your jobsites:

Why workers die

The leading reason for OSHA trench violations is failure by the employer to provide adequate cave-in protection.

Other violations include:

  • Failure to provide a ladder or other proper means of entering and exiting a trench.
  • Placing spoil too close to a trench where rock and dirt could fall in on employees.
  • Failure to provide daily inspections of excavations.
  • Failure by the designated competent person on the jobsite to protect workers from potential cave-in.
  • Hazards created by water accumulating in a trench.

How not to die

Under OSHA regulations, all trenches and excavations 5 feet or deeper must have some form of cave-in protection. OSHA-approved protection systems follow the "Three S's" and consist of one of the following methods:

  • Slope or bench trench walls by cutting back the trench wall at an angle inclined away from the excavation.
  • Shore trench walls by installing aluminum hydraulic or other types of supports to prevent soil movement.
  • Shield trench walls by using trench boxes or other types of supports to prevent soil cave-ins.

Trenches 20 feet or deeper must have protective systems designed by a registered professional engineer.

The National Utility Contractors Association notes that trenches as shallow as 3 to 4 feet deep can also prove fatal, and they should be inspected by a competent person before entering. OSHA requires a jobsite to have a competent person designated to look out for hazards and keep workers safely from them.

Never do this

Along with cave-in protection, OSHA says a trench or excavation should never be entered unless the following conditions are met:

  • It has some form of cave-in protection.
  • It has been properly inspected by a competent person.
  • There is a safe way to enter and exit trenches 4 feet or deeper, such as a ladder with its top at least 3 feet above the trench edge.
  • Equipment and materials are at least 2 feet away from the edge.
  • It is free of standing water and atmospheric hazards.

Always do this

NUCA also offers the following safety tips:

  • Locate all underground utilities before digging.
  • Stay inside the area that has been sloped, shored or shielded. Don't work outside it – not even for a moment.
  • Eliminate or control water accumulation before entering the trench.
  • Stay alert when working in or near previously disturbed soil conditions.
  • Keep vehicles away from the edge of the trench.
  • Check regularly for hazardous materials and oxygen levels in the trench.
  • Make sure running machines are always attended.
  • Use a ladder or ramp to get in and out of the trench. Place the ladder inside the protective system.
  • Stay off of shoring or shields and don't ride in buckets or on crane hooks.
  • Wear hard hats when working in or around trenches.
  • Stay out from under raised loads.