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813 Construction Worksite Safety
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Excavation and Trenching

Introduction

Two workers are killed every month in trench collapses. An excavation is any man-made cut, cavity, trench, or depression in an earth surface formed by earth removal.

Trench (Trench excavation) means a narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 meters).

Dangers of Trenching and Excavation

Cave-ins pose the greatest risk and are much more likely than other excavation-related accidents to result in worker fatalities.

Trench Cave-In

Other potential hazards in trenches include falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment. If you were to be buried by one cubic yard of soil, the weight a car would be pressing down on you.

An unprotected trench is an early grave. Do not enter an unprotected trench.

Knowledge Check Choose the best answer for the question.

5-1. What poses the greatest risk to workers at an excavation site?