Trenches can be dangerous worksites, but hazards associated with trench work are well-defined and preventable. There is no reliable warning when a trench fails, so they run the risk of suddenly collapsing, and it's easy for objects to fall into them. Workers who spend a lot of time in trenches need to be extra careful and should take care to follow these guidelines.
The most important thing that workers need to know before they begin digging a trench is what's underground. Gas lines, water pipes, and electrical wires are often buried, so supervisors and managers need to check with the local government to make sure that digging won't cause a flood, explosion, or electrocution. A competent person, or one who the Occupational Safety and Health Administration (OSHA) defines as being familiar with government regulations, can recognize hazards, and is authorized to correct them, needs to be on hand to judge the soil and landscape of an area before a trench is dug.
Any trench that is deeper than 5 feet needs to have supports in place, and any trench that is 20 feet deep or more is required by law to have supports that have been designed by an engineer. One of the easiest ways to do this is by sloping the walls of a trench down toward the bottom, giving support to the sides. Sometimes strong metal supports need to be installed to keep the walls up. This process is called shoring and is important to adhere to in very deep trenches.
Heavy equipment and spoil piles from the excavation should be kept at least 2 feet from the edge of the trench. During project planning, safe locations and heavy equipment routes should be mapped out to avoid cave-ins. Always wear the proper safety products as an added precaution.