Unprotected trenches are among the most dangerous hazards a construction worker can face; between 2003 and 2011, more than 200 workers have been killed in trench cave-ins. Hundreds more have been seriously injured. To help combat this problem, OSHA has produced a number of guidance documents aimed at keeping construction firms in compliance with OSHA 29 CFR 1926.651 and 1926.652 (as well as their counterparts from state-approved plans).
An excavation is any man-made cut, cavity, trench or depression in the earth surface formed by earth removal. Trenches (a trench excavation) are 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 the trench (measured at the bottom) is not greater than 15 feet.
Cave-ins are the most deadly accident to take place at excavation sites, many accidents involving falls, falling loads, hazardous atmospheres and incidents involving mobile equipment are reported each year. Storing excavated material or equipment within 2 feet of the trench’s edge makes the trench especially susceptible to cave-ins. It’s important to have sloped or stepped walls (if the soil allows), or a protective system to prevent an accident.
Employers must have a “competent person” inspect trenches daily, and as conditions change, before workers are allowed to enter. A competent person is an individual who is capable of identifying existing and predictable hazards or working conditions that are hazardous, unsanitary, or dangerous to workers, soil types and protective systems required, and who is authorized to take prompt corrective measures to eliminate these hazards and conditions.
Workers should be able to identify hazards quickly and know when to evacuate a dangerous area. Furthermore, it’s essential that employees understand how to safely enter and exit a trench; workers must be within 25 feet of an exit at all times.
You can find more information on trenching, trenching hazards and OSHA’s standards regarding trenching by visiting www.osha.gov/SLTC/trenchingexcavation/index.html. To access specific regulations for your state, visit www.osha.gov/dcsp/statestandard.html.