Watching Isn't Enough

LESSONS LEARNED

Workers doing activities in and around trenches and excavations must be alert to the real possibility of a trench cave-in. In most situations, a cave-in is likely to happen if there is no protection and workers should be aware of the specific type of protection they need to keep them safe while working in a trench or excavation. The most important rule is to never enter an unprotected excavation or trench!

OSHA Standard 1926.652(a)(1) Each employee in an excavation shall be protected from cave-ins by an adequate protective system…

Unprotected Trench Turns Into Deadly Cave-in

A 24-year old worker died when he was buried under a wall of the trench he was working in. The excavation had no cave-in protection. The excavation wall and part of the sidewalk next to the concrete garage floor collapsed onto him while he was attempting to attach a new PVC pipe. One coworker was also caught in the collapse. Two other workers on site, neighbors who heard their calls for help, and firefighters who arrived on the scene were able to get the coworker safely pulled from the excavation. However, the other worker died and his body was only able to be recovered from the excavation about 8 hours after the wall had collapsed. Read more >> NIOSH Michigan Case Report 05MI084

 View of the excavation from west to east showing the widest part, the area of collapse, the vertical sides and spoils.

View of the excavation from west to east showing the widest part, the area of collapse, the vertical sides and spoils.

 Pieces of sidewalk in the collapsed area and the garage slab foundation separated from the foundation. Notice, there is no protection in place to avoid the cave-in hazard.

Pieces of sidewalk in the collapsed area and the garage slab foundation separated from the foundation. Notice, there is no protection in place to avoid the cave-in hazard.

 The cave-in protection seen here was only installed after the fatal collapse so that the deceased worker could be safely be removed.

The cave-in protection seen here was only installed after the fatal collapse so that the deceased worker could be safely be removed.

The owner of this company was self-employed and had been doing sewer work for about 8 years on his own. The owner was not a licensed plumber or contractor. He had never used a trench box and his proclaimed method of working was "get in, fix it, get out."

The victim was the owner's son and had worked for this company for about 7 years. The company had no safety training program. Their method of "trench protection" was that during an excavation, like this one, someone was stationed at the top of the trench to "watch the dirt." The lookout would look for cracks and slow-moving or shifting dirt. If the lookout saw these signs, he would shout something like, "Dirt is coming". At that warning the workers in the trench were to stand up and put their hands in the air.

Recommendations provided after this incident investigation include:

  • Employers and self-employed contractors should slope or shore or use trench boxes in all excavations greater than 5 feet deep.
  • Employers and self-employed contractors should ensure that excavations are inspected by a competent person prior to start of work and as needed throughout a shift to look for evidence of any situation that could result in possible cave-in.
  • Employers and self-employed contractors should design, develop, and implement a comprehensive safety program that includes training in hazard recognition and avoiding unsafe conditions.
  • Emergency medical services and fire-rescue personnel should be knowledgeable about proper rescue techniques involving excavation sites and ensure that adequate shoring equipment is on hand at all times.

To read more about this incident, please review the case report: NIOSH Michigan Case Report 05MI084

In addition to ensuring a written safety program is in place and proper trenching and excavation procedures are followed on every job site, there should be regular safety meetings held to ensure all employees are reminded of safe practices when it comes to trenching and excavation.

Weeklysafety.com provides hundreds of safety meeting topics and toolbox talks, including safety meeting kits on cave-in protection. Download 10 free safety topics now (no credit card required) and then start your risk-free subscription to Weeklysafety.com for only $27/month.

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