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. Workers die every year when they are caught in an excavation or trench cave-in.
The FIRST RULE is to never enter an unprotected excavation or trench!
All excavations and trenches must be inspected by a Competent Person before workers enter them.
Excavations more than 5 feet deep must have cave-in protection.
A safe way to enter the excavation or trench is required when it is 4 feet or deeper.
OSHA Standard 1926.652(a)(1) Each employee in an excavation shall be protected from cave-ins by an adequate protective system designed in accordance with paragraph (b) or (c) of this section except when: (i) Excavations are made entirely in stable rock; (ii) Excavations are less than 5 feet (1.52 m) in depth and examination of the ground by a competent person provides no indication of a potential cave-in.
Before workers enter any excavation or trench it must be inspected by a Competent Person and there must be protection from a potential cave-in. Cave-in protection could be provided using any of the systems mentioned below:
Sloping or Sloping System - excavating to form sides of an excavation that are inclined away from the excavation so as to prevent cave-ins.
Benching or Benching System - excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels.
Trench Box, Trench Shield or Shield System - a structure that is able to withstand a cave-in and protect workers inside the shield or box. This is an option for almost all soil conditions and excavations and must be installed by trained personnel following the manufacturer's specifications.
Shoring or Shoring System - a structure such as a metal hydraulic, mechanical or timber shoring system that supports the sides of an excavation and which is designed to prevent cave-ins.