OSHA (Occupational Safety and Health Administration) defines a trench as a hole in the ground that is deeper than it is wide. Trench rescue involves shoring up the sides of a trench, and digging a trapped worker out of a collapsed ditch.
Similar to a confined space entry, hazardous atmospheres and possible injuries while in a trench may cause the need for trench rescue techniques. Other hazards specific to trenches include trench wall collapse, and/or objects rolling or falling onto the victim from above.
Along with techniques learned in ropes and confined space, specialized training and equipment are used in trench rescue.