Trenching and excavation work can expose workers to a variety of serious hazards, including cave-ins, struck-by incidents, falls, hazardous atmospheres, and contact with underground utilities. Many excavation-related injuries occur because hazards were not identified before digging began or because proper protective measures were not in place.
From putting a shovel into the ground to excavating a large trench, employers and workers should understand the safety requirements that apply to excavation activities and the steps necessary to protect everyone on the job site.
OSHA Standard 1926.650(b) "Excavation" means any man-made cut, cavity, trench, or depression in an earth surface, formed by earth removal.
OSHA regulations consider any digging activity as excavating. Whether the work involves a small hand-dug hole, a utility installation, grading activities, or a large trenching operation, excavation hazards must be evaluated before work begins.
Before Any Excavation Begins
One of the most important excavation safety requirements involves locating underground utilities before digging starts.
Contact 811 Before Digging
Anyone who is doing any kind of excavating activity must call 811 from anywhere in the country a few days prior to working on excavations or trenches.
Underground utilities such as electrical lines, natural gas lines, water lines, communication cables, and sewer systems may be buried beneath the surface. Striking one of these utilities can result in serious injuries, fatalities, service interruptions, property damage, or environmental releases.
Even after utilities have been marked, workers should continue to exercise caution while excavating near identified utility locations.
Protection from Falling Materials
Excavation walls and surrounding ground conditions can create hazards from falling or rolling materials.
OSHA Standard 1926.651(j)(1) Adequate protection shall be provided to protect employees from loose rock or soil that could pose a hazard by falling or rolling from an excavation face.
Workers must be protected from rocks, debris, loose soil, or other materials that could fall into the excavation while they are working. Loose rocks should be scaled, scraped or knocked down from the sides of excavations or trenches to prevent them from falling onto workers.
Keep Materials Away from Edge
Spoil piles should be set back 2-feet from the edges of excavations to create a safer work area.
Keeping excavated material away from the edge helps reduce the risk of material falling back into the excavation and decreases additional stress on the excavation walls. Equipment, tools, and construction materials should also be positioned so they do not create struck-by hazards for workers below.
Water Creates Serious Excavation Hazards
Water can quickly change excavation conditions and significantly increase the risk of cave-ins and other incidents.
OSHA Standard 1926.651(h)(1) Employees shall not work in excavations in which there is accumulated water, or in excavations in which water is accumulating, unless adequate precautions have been taken to protect employees against the hazards posed by water accumulation.
Water saturated trenches and excavations are extremely dangerous for those working inside of them. Never work in unprotected trenches or excavations that have water accumulating or are water saturated.
Control and Monitor Water Accumulation
Water pumps or other devices should be used to control water seeping into trenches and excavations. All water control devices must be inspected and maintained.
Standing water can weaken soil stability, hide hazards, create slip and fall risks, and make it difficult for workers to exit quickly during an emergency. Groundwater, broken utility lines, runoff, and rainfall can all contribute to water accumulation inside an excavation.
Excavation Inspections
Excavation conditions can change throughout the day. Soil conditions, weather, equipment activity, and nearby operations may all affect the stability of the excavation.
OSHA Standard 1926.651(h)(3) Excavations subject to runoff from heavy rains will require an inspection by a competent person.
Changing Conditions During Excavations
Heavy rainfall, freezing and thawing cycles, nearby traffic, vibration from equipment, and changes in soil moisture can all affect excavation safety. Conditions that appeared safe at the beginning of a shift may become hazardous later in the day.
Workers should remain alert for signs of changing conditions such as cracks in the soil, sloughing material, bulging excavation walls, water accumulation, or any indication that the excavation may be becoming unstable.
Excavation Safety Requires Planning
Excavation work should never be approached as a routine task. Every excavation presents unique hazards that must be evaluated before work begins and continuously monitored throughout the project.
Hazard Recognition During Excavation
Successful excavation safety starts with planning, hazard recognition, communication, and following established safe work practices. Utility locating, spoil pile management, water control, inspections, and protection from falling materials all play important roles in preventing injuries.
Taking the time to identify hazards before digging begins can help prevent incidents and ensure workers return home safely at the end of the day.
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