OSHA Excavation Regulations

The Occupational Safety and Health Administration (OSHA) is a U.S. agency dedicated to increasing the safety of employees. OSHA standards govern safety in all industries, but some fields are more heavily regulated due to increased risks inherent in these fields. One of the most strictly regulated fields is the construction industry, where employees face numerous dangers while performing their day-to-day work. Some of the biggest dangers to construction workers may occur during excavation. This is the process by which the soil on the site is dug up to make room for building foundations and underground utility work. All OSHA excavation regulations are strictly enforced, with significant financial penalties levied on non-compliant contractors.

Underground Lines

Buried below the earth's surface, excavators will find electrical power lines, phone wiring, gas and fuel piping, complex water systems, and even fiber optic cables. If an excavator were to dig into any of these items, he could face electrocution, flood dangers or exposure to hazardous materials. To minimize risks,OSHA requires that the location of all underground utilities on the site be marked before any excavation can begin. Generally, this involves a state or local public agency visiting the site to spray paint along the earth above lines or buried equipment. If local agencies are unresponsive or unavailable within 24 hours of a request being made, OSHA allows the contractor to locate and mark lines themselves using metal detectors and drawings of existing lines.

Means of Egress

For trenches deeper than 4 feet (1.2 meters) the contractor must provide a safe means of egress, or method of exiting the trench. This may consist of a ladder, stairway or ramp. Ramps and stairways must be designed by a structural engineer, or person with equivalent experience. Ramps built from more than one section of material must be safely joined to prevent falls and hazards. All structural members must be the same size and thickness, and ramps must be equipped with cleats or a non-skid surface treatment.

Equipment Operation

Employees are not permitted to be inside a trench where excavators or other equipment are digging or moving materials. All personnel on the job site should be trained to understand the operation of the machinery being used, and to stand clear while it is in operation. All machines that will be operating around a trench should be provided with a warning system to prevent the possibility of the equipment falling into the space. Warning systems may include hand signals, flag men or physical barricades.

Air Quality

When digging deep underground, employees may become exposed to hazardous gases or low oxygen levels. When employees are entering a trench deeper than 4 feet (1.22 meters), OSHA requires that air quality testing be performed if there is any possibility of poor air quality. This includes any setting where oxygen deficiency or hazardous materials are a concern. OSHA defines oxygen deficiency as an atmosphere containing 19.5 percent oxygen or below. In any potentially hazardous setting, emergency rescue equipment must be ready nearby. This should include breathable oxygen supplies, stretchers, ropes and harnesses.

Excavation Safety

One of the biggest threats during the excavation process is the possibility of a cave-in. This may include the soil around the trench or nearby structures that become unstable due to digging. To minimize this risk, all trenches must be equipped with an appropriate stabilization system. This may include shoring, underpinning or bracing to protect the stability of the soil. OSHA forbids any excavating below the level of the building's foundation without a review by a professional structural engineer. The engineer must deem the excavation safe, or design an underpinning system that will maintain the stability of the area.