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668 HAZWOPER for General Site Workers IX
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Excavation and Trenching

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.

Check out this Oregon OSHA video in which a worker is almost buried in a trench cave in. It's likely that the Oregon OSHA inspector cited the employer.

Trench Cave In

Other potential hazards include falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment. One cubic yard of soil can weigh as much as a car. 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 is the greatest risk workers face while performing tasks in a trench?