A recent presentation by MN OSHA reviewed hazards associated with trench work and three trench-related fatalities. There has been at least one trench fatality per year in Minnesota. In the last four years, there have been five fatalities in trenches – two of which involved employees installing a water line in frozen ground.
Some things to keep in mind when working in or around trenches:
- Competent person must inspect the trench or excavation every day.
- Competent person must have authority to stop a job if it isn’t safe.
- Frozen soil is not protection against collapse. Soil has to be treated the same regardless of how hard it is to dig.
- Any water in the trench will decrease the integrity of the walls.
- Using a trench box offers the greatest level of protection, although shielding and proper sloping is allowed.
- Nearby roadways may contribute vibration to the soil, reducing its integrity.
- Employees must be trained on hazards of their work, how to identify soil, what is an adequate protective system and other hazards with their job.