OSHA issued a compliance directive for its excavation standard on July 1, 2021. The directive provides guidance and inspection procedures for the enforcement of the standard.
The directive includes changes for inspection guidance and citation policy provisions, general inspection procedures, standard interpretations and insertion of hyperlinks to referenced OSHA documents.
The compliance directive is intended to serve as a resource or standard-specific reference for OSHA Compliance Safety and Health Officers (CSHO) regarding the application of the excavation standard.
This summarizes the guidlines CSHOs are directed to follow when enforcing the excavation standard. This will provide employers some insight into how CSHOs inspect excavation sites.
Employers should review the compliance directive to gain a better understanding of how CSHOs will inspect excavation worksites. Employers can also use this article to prepare for OSHA inspections.
General Inspection Procedures for Excavations
Guidance for worksite inspections where excavation is present requires CSHOs to obtain and include the following information in a case file for the inspection:
- Photographs or video of the excavation;
- Sketches of the excavation;
- Soil samples and analysis;
- Excavation measurements;
- Employee exposure documentation; and
- A copy of the excavation protection program.
This section of the compliance directive provides inspection guidance and a discussion of citation policies that CSHOs must follow.
Surface Encumbrances (29 CFR § 1926.651(a)) Surface encumbrances are discussed under specific excavation requirements. CSHOs will visually inspect the area in and around the excavation. They will note surrounding excavation conditions such as utility poles, fence lines, trees or structures such as pavement, sidewalks, curbs or walls.
Employers must endeavor to remove or support surface encumbrances whenever these conditions are present during excavation. Employees will be interviewed by CSHOs to determine whether they responded sufficiently to existing surface encumbrances. CSHOs can issue citations to employers that do not respond adequately to existing surface encumbrances.
Underground Installations (29 CFR § 1926.651(b)) This standard establishes minimum criteria regarding the employer’s responsibility to locate and address utility installations reasonably expected to be encountered during excavation operations. Underground installations include all types of utility lines either in service or abandoned, including sewer, telephone, fuel (gas or liquid), electric and water lines. They also include foundations and underground storage tanks.
Employers must comply with the requirements to locate and address utility installations. CSHOs will determine compliance by:
- Inspecting the excavation to determine whether underground installations were present.
- Establishing through interviews whether the employer called 811 (the designated nationwide number for contractors to call prior to excavating) or contacted the appropriate local utility companies to locate underground installations prior to excavation work.
CSHOs will document the following if underground utility installations are present:
- Was the appropriate utility company or owner involved contacted within established or customary local response times?
- Who contacted the utility company?
- Was the utility company advised of proposed work?
- If the utility company or owner could not respond within 24 hours (or the minimum time established by state or local law), did the employer proceed with caution and use detection equipment or other means to locate utility installations?
- Were the underground installations protected, supported or removed as necessary to safeguard employees?
- Written verification of contact with the utility company (e.g., email confirmation) and any provided location documentation.
In addition, if the employer uses its own detection equipment or other means to locate utility installations, CSHOs must ask to see the equipment used. Often, metal rods with uninsulated handles are used. Such tools pose a potential electrocution hazard.
CSHOs will consider a citation for the employer for the following reasons:
- If the locations of utility installations were not estimated prior to opening the excavation.
- If the utility company or owner was not contacted within established or customary local response time to communicate the project scope and request utility location. (If the utility company or owner could not respond within 24 hours—or a longer period required by state or local law—and an exact location could not be determined, the employer may proceed if detection equipment or other means to locate utility installations are used.)
- If the excavation operation approaches the estimated location of a utility installation and the employer failed to determine the exact location of the utility installation, or attempted to determine the location but did not use safe or acceptable means to do so.
- If underground installations are not protected, supported or removed as necessary to safeguard employees while the trench or excavation is open.
CSHOs will issue a citation to employers for not properly following the excavation standard requirements.
Access and Egress (29 CFR § 1926.651(c)) This section establishes requirements for safe access to and egress from excavations. A ramp built of steel or wood, usually used for vehicle access, is the minimum criteria for the design and construction of a structural ramp. A ramp made of soil or rock is not considered to be a structural ramp. This section is intended to prevent the collapse of structural ramps due to under-designed members or connections. It requires adequate means of egress be provided in the area where employees are working.
CSHOs must verify employers have provided ladders, steps, ramps or other safe means of egress for workers working in trench excavations at least four feet deep. No worker should be required to travel more than 25 feet laterally within the trench to reach the means of egress. The point of egress would be inadequate if the area is larger than 25 feet and employees would reasonably be expected to venture beyond 25 feet from the egress.
The sloped end of a trench (for example, an earth ramp) may be considered a safe means of egress if the earth ramp was designed for such use. In determining whether or not the earth ramp can be used for safe egress, CSHOs must consider such factors as the:
- Degree of the slope;
- Depth of the excavation;
- Soil and environmental conditions; and
- Presence of any obstructions.
Any structural ramps used for employee or equipment access or egress must be designed by a competent person qualified in structural design. Structural ramps must be inspected by CSHOs for other potential deficiencies. Structural members used for ramps or runways must be uniform in thickness, and designed and joined in a manner to prevent tripping or displacement.
Employers will be in violation of the standard if structural ramps were not designed by a competent person, if a trench excavation is at least four feet deep with no safe means of egress, or if workers have to travel further than 25 feet laterally for egress.
Exposure to Vehicular Traffic (29 CFR § 1926.651(d)) Under the standard, employers must provide employees who are exposed to vehicular traffic with warning vests or other suitable reflective or high-visibility garments to reduce the risk of being struck by traffic. When CSHOs complete an inspection of an excavation near a roadway and employees are not provided with high-visibility garments, the employer will be found in violation of the standard.
Exposure to Falling Loads (29 CFR § 1926.651(e)) Employees are prohibited from being underneath loads and exposed to the hazard of being struck by any spillage or falling material while vehicles are loaded or unloaded during excavation activities.
CSHOs must look for gravel or other material being dumped into or in proximity to the excavation while employees are working underneath. They will evaluate where the materials are being dumped relative to the employees’ location.
Employees should be at a distance sufficient to avoid being struck by dumped materials. The prohibition against employees working under loads handled by lifting or digging equipment includes excavated materials as well as slung loads (for example, pipes). However, the operator is permitted to remain in the cab of a vehicle being unloaded or loaded, provided the cab has a shield or canopy that is adequate to protect the operator from shifting or falling materials.
Employers can be cited for a violation of the standard if:
- Equipment is adjacent to, or has the potential to go beyond, the edge of an excavation;
- The operator does not have a clear, direct view of the edge; and
- A warning system was not used.
Warning Systems for Mobile Equipment (29 CFR § 1926.651 (f)) Employers are required to use adequate warning systems with mobile equipment. Employers must use warning systems such as stop logs, chock blocks, barricades or hand or mechanical signals to remind mobile equipment operators of their proximity to excavations.
CSHOs must determine whether an adequate warning system was provided for mobile equipment operating adjacent to or without a clear view of the edge of the excavation. If warning systems were not provided, the employer is in violation of the standard and will be at risk for a citation for that violation.
Hazardous Atmospheres – Testing and Controls (29 CFR § 1926.651(g)(1)) Employees must be protected when working in excavations deeper than four feet in locations where hazardous atmospheres are likely. Adequate precautions and controls, such as atmospheric testing, ventilation, and respiratory protection must be provided to prevent employee exposure to atmospheres containing less than 19.5% oxygen, as well as other hazardous atmospheres.
The standard requires atmospheric testing when a hazardous atmosphere could reasonably be expected to exist. CSHOs must evaluate the likelihood of hazardous atmospheric conditions based on the work activity in the excavation and surrounding factors or conditions. If an atmospheric hazard could reasonably be expected to exist, the employer must test the atmosphere. CSHO inspections will include asking the competent person or other employer’s representative on site if hazardous atmospheres could reasonably be expected to be encountered and, if so, whether testing was conducted, and the results of that testing. CSHOs must ensure that the employer had the proper equipment for testing the atmosphere to verify whether a hazardous atmosphere was present, and if the requirements for respiratory protection or ventilation were met. If the requirements were not met, the employer is in violation of the standard and will be at risk for a citation for that violation.
Emergency Rescue Equipment (29 CFR § 1926.651(g)(2)) Employers must take additional precautionary measures to ensure that emergency rescue equipment is available if hazardous atmospheric conditions exist or may reasonably be expected to develop. This standard requires that employees entering bell-bottom pier holes or similar deep and confined-footing excavations wear a harness with a lifeline and be attended to while in the hole.
If hazardous atmospheric conditions exist onsite, or may reasonably be expected to develop, CSHOs must determine the availability of emergency rescue equipment, such as a:
- Breathing apparatus;
- Safety harness and line; or
- Basket stretcher.
If the work involves employees entering into deep and confined-footing excavations, such as bell-bottom pier holes, CSHOs must determine through observation or interviews whether:
- The employees have used/are using a harness and lifeline,
- Employees in the hole were attended to at all times, and
- The lifeline is separate from any line used to handle materials.
CSHOs must document the presence of any work operations or hazardous atmospheric conditions that may trigger these requirements. If emergency rescue equipment is not readily available where hazardous atmospheric conditions existed or could reasonably be expected to develop, or if employees using emergency rescue equipment were not attended to, an employer will be in violation of the standard and will receive a citation.
A citation will also be issued if employees entering bell-bottom pier holes, or other similar deep and confined footing excavations, did not wear a harness with a lifeline securely attached to it or if the lifeline was not separate from any line used to handle materials.
Water Accumulation Hazards (29 CFR § 1926.651(h)) Employers are prohibited from allowing workers to enter an excavation where water has accumulated or is accumulating unless precautions are taken to protect workers. A competent person must inspect the excavation that is subject to runoff from heavy rains. Diversions must be provided to prevent surface water from entering or provide adequate drainage of adjacent areas.
If water is observed in an excavation, CSHOs must document all evidence of employee exposure to the water hazard, as well as accumulated water in the excavation. If there is water in the excavation and no evidence of actual or potential employee exposure, then there is no violation of the standard.
Stability of Adjacent Structures (29 CFR § 1926.651(i)) Employers are required to provide support systems, such as shoring, bracing or underpinning, when necessary to ensure that adjacent structures (including adjoining buildings and walls) remain stable for the protection of workers. The standard requires similar support for sidewalks, pavements and appurtenant structures. Excavations below the level of the base or footing of any foundation or retaining wall that could pose a hazard to employees are not permitted unless a support system, such as underpinning, is provided, the excavation is in stabile rock, or a registered professional engineer has determined there is no hazard.
During an inspection CSHOs must determine whether there are buildings, walls, sidewalks, pavement or other adjacent structures that are or could be compromised or subject to collapse due to excavation operations. Employers must provide support systems, unless the excavation is in stable rock or a registered professional engineer has determined no hazard is present.
Employee Protections from Loose Rock or Soil (29 CFR § 1926.651(j)) Employers must address hazards associated with loose rock or soil that could fall from the face of an excavation, spoil piles or equipment that could fall or roll into the excavation.
CSHOs must examine the perimeter of the excavation for potential loose soil or rock hazards, spoil piles or banks, other materials or equipment that may be within two feet of the edge of the excavation. If there are hazards identified, CSHOs must make observations and interview employees to determine whether there is reasonable danger to employees from objects falling into the excavation and causing harm. If there is a reasonable danger to employees or materials are placed within two feet of the edge of the excavation, an employer will be in violation of the standard.
Inspections (29 CFR § 1926.651(k)) When employee exposures can reasonably be anticipated, employers must have a competent person perform inspections. This means an inspection must be performed any time an employee is expected to work in an excavation. During the course of work in an excavation, hazards may develop due to changing conditions at the worksite. The purpose of an inspection is to identify any hazardous conditions and implement corrective actions to protect employees. Inspections must be conducted at the following times:
- Daily, prior to the start of each shift.
- As needed throughout each shift.
- If there are changes in the excavation or surrounding conditions that could increase hazards.
- After every rainstorm.
- After other events that could increase hazards, such as a snowstorm, windstorm, thaw, earthquake, etc.
- When fissures, tension cracks, sloughing, undercutting, water seepage, bulging at the bottom or other similar conditions are present.
When a competent person finds evidence of conditions that could result in a cave-in, indications of failure of existing protective systems, hazardous atmospheres, or other hazardous conditions, the competent person must exercise the authority to remove employees from the hazardous area.
CSHOs must determine whether daily inspections were conducted by an onsite competent person or others. If inspections were not conducted, CSHOs must determine the reason and whether employees were expected to enter the excavation to complete work. If there is evidence of hazards, such as a situation that could result in a possible cave-in, failure of a protective system, or employees exposed to hazardous atmospheres, and employees were not removed from the excavation, the employer is in violation of the standard.
Walkways (29 CFR § 1926.651(l)) Employers must provide guardrails for walkways that are six feet or more above a lower level when employees or equipment are required or permitted to cross over excavations. During an inspection, if there are walkways that cross over an excavation, CSHOs must measure the height of the walkway to determine whether adequate guardrails have been provided.
Employee Protection in Excavations (29 CFR § 1926.652 (a)) Employers must provide adequate protective systems to protect employees from cave-ins. These systems must meet the particular requirements in the standard that cover sloping, benching or support systems, shield systems and other protective systems.
The standard does not require the installation and use of protective systems when an excavation is made entirely of stable rock or if it is less than five feet deep and a competent person has inspected and found no indication of potential cave-in hazards.
CSHOs must inspect the excavation and determine whether the excavation needed a protective system and if one was used. If a CSHO finds that employees are working in an excavation that is not entirely made of stable rock, and that a competent person failed to assess that there was no indication of a potential cave-in, the employer will be in violation of the standard.
Employers must design protective systems to meet the requirements of the standard. If a system does not appear adequate or seems in danger of failure, the employer’s representative or competent person must be notified immediately so employees can be removed from the excavation until the hazard has been abated.
Sloping and Benching System Designs (29 CFR § 1926.652(b)) Employers have four options to follow when designing and constructing sloping and benching systems for protecting employees working in excavations:
- Allowable configurations and slopes. Under this option, the excavation sides must be sloped at an angle that is not steeper than 1½ horizontal to one vertical (1.5H:1V, 34 degrees measured from the horizontal). Employers may cut the excavation to the slope specified by this option, without the need for initial testing and classifying the soil at the excavation site.
- Slopes and configuration with use of Appendices A and B. Under this option, the benching or sloping system for the excavation must conform with the requirements of Soil Classifications in Appendices A and B to Subpart P. Appendix A – Soil Classification contains methodology for the employer to use to define soil types. Appendix B – Sloping and Benching provides specifications for sloping and benching that must be followed for the employer to comply with Option 2 under the standard.
- Designs using other tabulated data. This option allows the employer to design a sloping and benching system in accordance with tabulated data, such as tables and charts, approved by a registered professional engineer. This data must be in writing and include explanatory information, including the criteria for selecting a system and the limits on the use of the data. At least one copy of the data, which identifies the registered professional engineer who approved it, must be kept at the worksite during installation of the protective system. After the system is completed, the data may be stored away from the job site, but the employer must provide a copy to OSHA upon request.
- Registered professional engineer design. Under this option, sloping and benching systems that do not meet the criteria of Option 1, Option 2 or Option 3 are permitted if the design is approved by a registered professional engineer. The design must be in writing and include the magnitude of the slopes and configurations that were determined to be safe for the particular project. The design must also include the identity of the registered professional engineer who approved it. At least one copy of the design must be kept at the worksite while the protective system is being installed. After the system is completed, the data may be stored away from the job site, but the employer must provide a copy to OSHA upon request.
CSHOs must evaluate whether the sloping and benching systems have been designed and constructed in accordance with the options above under the standard. If the protective system was designed by a registered professional engineer, the CSHO must request to see a copy of the design and verify the registered professional engineer’s credentials to ensure the engineer is working within their respective discipline. If an employer does not meet the specific criteria of sloping or benching it is in violation of the standard.
Support Systems, Shield Systems and other Protective System Design (29 CFR § 1926.652(c)) Employers have four alternatives for the design and construction of support systems, shield systems and other protective systems:
- Designs using Appendices A, C and D. Under this option, designs for timber shoring must conform with the requirements in Appendices A and C to Subpart P of the OSHA excavation standard. Designs for aluminum hydraulic shoring must be in accordance with 29 CFR § 1926.652(c)(2), but if the manufacturer’s tabulated data cannot be used, the designs must be in accordance with Appendix D to Subpart P of the OSHA excavation standard. Appendix A – Soil Classification contains methodology for the employer to use to define soil types. Appendix C – Timber Shoring for Trenches provides specifications for timber shoring as a method of protection from cave-ins in trenches that do not exceed 20 feet in depth. Appendix D – Aluminum Hydraulic Shoring for Trenches provides specifications for when aluminum hydraulic shoring is provided as a method of protection from cave-ins in trenches that do not exceed 20 feet in depth. See Appendices A, C, and D and Chapter 2 of the OSHA Technical Manual for additional information.
- Manufacturer’s tabulated data designs. Under this option, employers are required to design support systems, shield systems or other protective systems from the manufacturer’s tabulated data. The design must follow all the manufacturer’s specifications, recommendations and limitations. Deviations are only permitted with the manufacturer’s approval. The manufacturer’s specifications, as well as any approval of deviations, must be in writing, and at least one copy of this written information must be kept at the worksite during installation of the protective system. After the system is completed, the data may be stored away from the job site, but the employer must provide a copy to OSHA upon request. Note that under this option, there is no requirement that the manufacturer’s tabulated data identify a registered professional engineer.
- Tabulated data designs. This option requires the employer to design support systems, shield systems or other protective systems from tabulated data other than the manufacturer’s tabulated data. This data must be in writing and must include an identification of the parameters that affect the selection of a protective system drawn from the data, any limits of the use of the data, any explanatory information to assist in making a correct selection of a protective system, and the registered professional engineer that approved the data. At least one copy of the written information must be kept at the worksite during installation of the protective system. After the system is completed, the data may be stored away from the job site, but the employer must provide a copy to OSHA upon request.
- Registered professional engineer design. Under this option, support systems, shield systems and other protective systems that do not meet the other three alternatives above (designs using appendices A, C and D; manufacturer’s tabulated data; and tabulated data designs) are permitted if the design is approved by a registered professional engineer. The design must be in writing and include the sizes, types, and configurations of materials used in the protective system and the name of the registered professional engineer approving the design. At least one copy of the design must be kept at the worksite during the construction of the protective system. After the system is completed, the data may be stored away from the job site, but the employer must provide a copy to OSHA upon request.
CSHOs must determine what type of protective system was used by the employer, and if the employer used a support system, shield system or other protective system besides sloping or benching. They will identify which option, if any, the employer followed and evaluate whether the systems were designed and constructed in accordance with the requirements.
Materials and Equipment (29 CFR § 1926.652(d)) The provisions in this standard are intended to prevent hazards resulting from damaged or defective components of protective systems. The materials and equipment used for protective systems must be free from damage or defects that might impair their proper function, and they must be used and maintained in a manner that is consistent with the manufacturer’s recommendations. Under the standard, a competent person must evaluate any damaged material or equipment used for protective systems to determine its suitability for continued use. If the competent person cannot insure its suitability for safe use, the material or equipment must be removed from service.
CSHOs must safely examine structural members of all protective systems in place at the excavation site for visible damage or defects. The first step of this process may include a general inspection by the CSHO of the protective system, to insure all manufacturer recommended components are in place.
Installation and Removal of Support Systems (29 CFR § 1926.652(e)) This section of the standard provides specific requirements for support systems, and their components and members, in excavations during the installation and removal process. Installation and removal of support systems, which can involve significant material-handling activity, are particularly hazardous periods in excavation work. Additionally, partially completed support systems will not react to loads in the same manner as completed structures. Individual members can become overloaded and fail, leading to a general failure of other portions of the support system. Therefore, employees can be exposed to cave-ins, the collapse of adjacent structures, or collapse of the support system if the employees are not properly protected during installation and removal.
CSHOs must review the support system components to make sure they were connected, installed or removed properly. During this review, CSHOs must make sure additional precautions were taken to ensure the safety of employees.
Sloping and Benching Systems (29 CFR § 1926.652(f)) This standard prohibits employees from working on the faces of sloped or benched excavations at levels above other employees, unless employees at lower levels are adequately protected from falling, rolling or sliding material and equipment hazards.
CSHOs must determine during an inspection whether the employees working below were protected from hazards created by operations conducted above on the sloped and benched faces. If the employees were not protected, the employer will be in violation of the standard.
Shield Systems (29 CFR § 1926.652(g)) Under the standard, shield systems, such as trench shields or trench boxes, may not be subjected to loads that exceed those which the system was designed to withstand. CSHOs must gather information from the employer to determine the shield system’s load limits, as well as the actual load placed on the system during work activity.
The standard requires shields to be installed to restrict lateral or other hazardous movement in the event sudden lateral loads are applied. Should a cave-in occur, the volume and force of the soil could potentially cause lateral movement of the shield. CSHOs must determine whether the employer’s competent person determined whether the shield was close enough to the wall to ensure that there would be no lateral movement. Generally, trench box manufacturers’ recommendations state that the excavated area between the outside of the trench box and the face of the excavation should be as small as possible. They will check the manufacturer’s literature, if available, for distance recommendations for any substantial gaps between the shield and the side walls of the excavation. During an inspection, CSHOs must also measure the width between the shield and the side wall of the excavation, in addition to the length and depth of the gap; these measurements will aid in determining the volume of soil which could collapse and potentially cause lateral movement.
Employees should not be inside a shield while they are being installed, removed or moved vertically. The standard requires employees to be protected from cave-in hazards when entering or exiting areas protected by shields. CSHOs must determine whether the ends of shields are protected from cave-ins and document the distance from the end of the trench shield to the exposed excavation wall.
- Compliance directive for the excavation standard
- Field operations manual
- Appendix A – soil classification
- Appendix B – sloping and benching
- Appendix C – timber shoring for trenches
- Appendix D – aluminum hydraulic shoring for trenches
- Appendix E – alternatives to timber shoring
- Appendix F – selection of protective systems
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