Workplace Safety Guides

   Underground Excavation


During an excavation project, all surface encumbrances such as trees and boulders that are located so as to create a hazard, must be removed or supported to safeguard workers. The estimated location of utility installations such as sewer, water, fuel, and electric lines, or any other underground installations that may reasonably be met with during excavation work are to be determined prior to opening the ground. Prior to the start of actual operations, the utility companies or owners are to be advised of the proposed work and asked to establish the underground installation's actual location.

When the utility or owner cannot establish exact locations or respond in a timely manner, the contractor may proceed with caution. Detection equipment or other acceptable means to locate utility installations must be used. When excavation work nears the estimated location of the installations, the exact location is to be found by safe and acceptable means.

While the excavation is open, underground installations must be protected, supported, or removed as is necessary to safeguard employees. Flooding, shock, asphyxiation, electrocution, fire, explosion, and collapse of undermined installations are some of the hazards that result when underground installations are damaged.

Structural ramps must be designed and constructed to meet the requirements of their usage. Safe means of entering and leaving excavations must be provided for workers. A stairway, ladder, ramp, or other safe means of egress must be located in trench excavations four feet or more in depth so as to require no more than 25 feet of lateral travel. This is to allow workers to get out quickly in the event of an emergency.

Employees exposed to public vehicular traffic shall be provided with, and must wear, warning vests or other suitable garments marked with or made of reflectorized or high visibility material. Employees are not allowed under loads handled by lifting or digging equipment. Employees must stand away from vehicles being loaded or unloaded to avoid being struck by spillage or falling materials. Operators may remain in the cabs of vehicles being loaded or unloaded when the vehicles are equipped to provide adequate protection for the operator during these operations.

When mobile equipment is operated next to an excavation or when it must approach the edge of an excavation and the operator does not have a clear direct view of the edge, a warning system must be used. This system may involve barricades, stop logs, or signals.

Index of Workplace Safety articles | Next Article: Air and Water Concerns During Excavation | Previous Article: Excavation Safety