Construction Laborer Died in Trench Wall Collapse, Michigan

SUMMARY

In fall 2017, a male laborer in his 30s died when a 7-to 8-foot deep trench wall collapsed. The decedent and the company owner were attempting to locate a clogged sewer pipe at a residential home. The company owner used an excavator to dig an approximately 70-foot long trench from the sidewalk to the house. The north/south side of the trench was located right next to the west side of the property’s driveway. The excavation was approximately 7- to 8-feet deep, 3- to 4-feet wide at the base and 5- to 6-feet wide at the top. The west wall of the excavation was at a 74-degree angle. The east wall of the excavation, right next to the driveway, was nearly vertical. The soils consisted of dry, coarse, brown sand with a gravel mix. The company owner placed the spoil piles on both sides of excavation. The two workers went into the excavation to hand dig to attempt to find the plugged areas and clean them out or replace the sewer. While in the excavation, the east trench wall (next to the driveway) collapsed, completely burying the decedent and burying the company owner to his neck. The company owner called out for help and a neighbor called for emergency response. An excavator was brought in to remove a portion of the spoils to allow for a vacuum truck to be positioned near the decedent’s location to remove the dirt surrounding him. The vacuum truck could not get close enough to remove all soil from around the decedent, so the responding fire department performed a trench recovery by placing shoring and bracing in the excavation around the deceased. This was the first time the company owner had performed a deep, long excavation.

CONTRIBUTING FACTORS

• Excavation protection (shoring, benching, sloping) was inadequate
• A qualified person did not inspect the trench or the soil type/compaction in the work area
• The company owner did not recognize the risks of working in an unprotected trench
• The company did not have a safety program or provide safety training
• The company did not acquire a permit for the sewer trench operation

RECOMMENDATIONS

• Employers should ensure that employees working in excavations are protected from cave-in by an appropriate protective system, such as trench boxes, shields, benching and/or appropriate sloping of trench sides designed in accordance with MIOSHA Construction Safety Standard, Part 9, Excavation, Trenching, and Shoring. To ensure this is done correctly, a qualified person must inspect and approve the excavation, adjacent areas, and supporting systems on an ongoing basis.
• Employers should ensure anyone working in or around trenches are trained to recognize and avoid hazardous work conditions. Employers should also ensure that the training in recognizing and avoiding hazards is coupled with employer assessment that workers are competent in the recognition of hazards and safe work practices. In addition, a job safety analysis (JSA) could be completed prior to working so that the hazards could be recognized.
• Employers and self-employed contractors should design, develop, and implement a comprehensive safety program that includes training in hazard recognition and avoiding unsafe conditions.
• Always obtain the appropriate construction permits prior to performing a construction activity.
• Emergency medical services and fire-rescue personnel should be knowledgeable about proper rescue techniques involving excavation sites.

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