The Occupational Safety and Health Administration (OSHA) defines an excavation as any man-made cavity in the earth’s surface formed by the removal of earth. A trench is a type of excavation in which its width at the bottom is generally no more than 15 feet and its depth is greater than the width. OSHA regulates labor practices in the United States under Title 29 of the Code of Federal Regulations (CFR), with Part 1926 addressing safety and health regulations for construction. Sections 650, 651 and 652 of Part 1926 deal specifically with excavation.
Excavation is one of the most hazardous operations in construction, due to the presence of an especially large number of hazards. Locators must therefore engage in many safety practices to minimize the risk of excavation to construction workers.
Table of Contents
Hazards
Locators routinely encounter a variety of safety hazards on a daily basis. The top 10 categories of locator safety hazards include the following:
- Confined spaces
- Threats to the eye
- Climate and weather
- Dog bites
- Puncture and foot trauma
- Poison ivy and other skin threats
- Insect bites and stings
- Walking, lifting, bending and squatting
- Slips, trips and falls
- Time on the road
Competent Person
OSHA regulations require a “competent person” to be in charge of any excavation site. This person has the authority to take corrective action in safety matters and must have specific training in 1926.651 subpart P, including on-the-job experience. The Federal Register also requires a competent person to be trained in soil analysis and the use of protective systems. The competent person for an excavation project inspects the site and equipment for hazardous conditions such as cave-ins, equipment failures and hazardous atmospheres. These inspections should be performed daily and after every rain.
Planning
Safe work practices begin in the planning phase of an excavation operation, which includes hazard recognition and soil analysis. Locators should perform a preliminary inspection of the area for signs of underground utilities such as fire hydrants, telephones and transformers. They should also call 811 before digging, which is a national number that provides information on underground utilities. The soil analysis is needed to determine the structural requirements for the excavation. The OSHA Construction E-Tool at includes a training program for trenching and excavation.
Surrounding Structures
Locators must mark the position of all underground utilities before starting the excavation. They may use a variety of tools for this purpose, including flags, paint, stakes and whiskers. These marks should be in an appropriate color with a length of 12 to 18 inches and a width of about one inch. They should be spaced four to 50 feet apart above the facility, depending on terrain, excavation type and marking method. Locators also need to stabilize adjacent support structures with appropriate techniques, including bracing, shoring and underpinning.
Equipment
An inspection of equipment before beginning the work is a standard part of any construction project. Excavation routinely involves the use of heavy machinery such as backhoes, which can pose a major safety hazard if they aren’t in good working order. Excavation also requires a particularly large amount of personal safety equipment, including the following:
- Hardhats
- Steel-toed boots
- Gloves
- Goggles
- Ear muffs
- Harnesses
Cave-ins
The possibility of a cave-in poses a major risk in excavations, requiring their construction to include various types of structural support and worker protection. The basic types of structural support for excavation include benching, shoring and sloping, while a trench box is the primary form of protection for excavation. Benching is the process of building a series of benches, or steps, in the sides of an excavation to minimize the damage caused by dirt sliding down the sides of the trench. Shoring involves reinforcing the sides of the excavation with timber or some other sturdy material to prevent the sides from collapsing. Sloping an excavation reduces the pressure that soil exerts on the sides.
Access
The access paths to an excavation must be carefully controlled to ensure worker safety, especially for deep trenches. Trenches with a depth greater than four feet generally require easy-to-use ladders or stairs to be placed at 25-foot intervals. Crossing a trench at its surface should be strongly discouraged, due to the risk of falling off a catwalk. The preferred method of crossing a trench is to descend on one side via stairs or ladder, walk to the other side and ascend.
Falling Objects
Falling objects are a common cause of excavation injuries due to the use of heavy machinery. Excavated material, commonly known as a spoil pile, should be kept at least two feet from the edge of an excavation. This practice generally requires the use of retaining devices, although it may be necessary to haul spoils to another location. Workers also need to remain clear of vehicles and other equipment while they’re loading and unloading materials. The prevention of water accumulation is generally an essential safety practice in construction, but it’s especially important around excavations.
Gases
Trenches can contain hazardous atmospheres due to either a low level of oxygen or high level of some other gas. Some trenches may have an atmosphere that requires workers to wear additional equipment such as masks or respirators. An excavation’s atmosphere must therefore be tested under the supervision of a competent person before workers enter and at regular intervals thereafter. The competent person for an excavation project must also take appropriate actions to reduce the hazard posed by the excavation’s atmosphere, which may include removing workers from the site until conditions improve.
Evaluation
Excavations should only remain open for the minimum amount of time needed to complete the project. The site should also be evaluated after its completion, largely for the purpose of improving safety practices. The results of the evaluation may then be incorporated into the planning phase of future operations, resulting in a pattern of continuing improvement.
All of Underground Services’s employees have safety training that includes OSHA-compliant courses, defensive driving and first aid. Contact us today at (610) 738-8762 or request a quote online to find out how we can help make your excavation project safer.
