Excavations

There is no reason why anyone ever has to die in a trenching accident. Modern technology has provided us with a variety of excellent shoring systems and trench shields. The OSHA excavations standard provides us with a set of clearly written and logical safety rules. Yet every year workers are killed and injured by cave-ins.

The Occupational Safety and Health Administration issued its first Excavation and Trenching Standard in 1971 to protect workers from excavation hazards. Since then, OSHA has amended the standard several times to increase worker protection and to reduce the frequency and severity of excavation accidents and injuries. Despite these efforts, excavation related accidents resulting in injuries and fatalities continue to occur.

OSHA revised the excavations standard in 1989, with focus on the existing standard to simplify many of the existing provisions, add and clarify definitions, eliminate duplicate provisions and ambiguous language, and give employers added flexibility in providing protection for employees.

In addition, the standard provides several new appendixes. Appendix A to 1926.652 provides a consistent method of soil classification. Appendix B to 1926.652 provides sloping and benching requirements. Other appendixes (appendixes C–F) provide pictorial examples of shoring and shielding devices, timber tables, hydraulic shoring tables, and selection charts that provide a graphic summary of the requirements contained in the standard. For more information on the details of proper installation, please refer to the OSHA standard on excavation (29 CFR 1926 Subpart P, which includes 650–652 and appendixes A–F) and to the Suggested Readings in this guide.

The OSHA standard applies to all open excavations made in the earth’s surface, which includes trenches. According to the OSHA construction safety and health standards, 1926.650(b), a trench is referred to as a narrow excavation made below the surface of the ground in which the depth is greater than the width—the width not exceeding 15 feet (4.5 meters). An excavation is any man-made cut, cavity, trench or depression in the earth’s surface formed by earth removal. This can include excavations for anything, from cellars to highways.

Proper selection and installation of trench protection measures are very important. To comply with the standard, the employer must have a competent person: “one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.”

After this module you should be able to Identify the most common excavation hazards and how to take steps to avoid those hazards.