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Write a risk assessment for Excavation

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A suitable excavation risk assessment should treat cave-in and ground collapse as the primary fatal hazard, while also addressing falls, falling loads, mobile equipment, utilities, water intrusion, hazardous atmospheres, and traffic exposure. OSHA excavation compliance is centered on 29 CFR 1926\.651 and 1926\.652, with a competent person assessing soil, site conditions, protective systems, adjacent loads, utilities, weather, and changing conditions before entry and throughout the work. [1] [2] [16]

Key risk assessment and control measures:

  • Define whether the work is an excavation or a trench, record dimensions, soil classification, water conditions, adjacent structures, traffic exposure, and nearby equipment loads before work starts.
  • Appoint a competent person with authority to stop work, inspect before entry, at the start of each shift, after rainstorms, water intrusion, and whenever site conditions change.
  • Use a protective system for trenches 5 feet or deeper unless the excavation is entirely in stable rock; for shallower trenches, require the competent person to determine whether cave-in protection is needed.
  • For trenches 20 feet or deeper, use a protective system designed by a registered professional engineer or based on engineer-approved tabulated data.
  • Select the protective method based on soil type, depth, moisture, weather, surcharge loads, utilities, and nearby operations: sloping, benching where permitted, shoring, or shielding/trench boxes.
  • Do not allow entry into an unprotected trench. Fatal case history shows deep trenches in unstable soil without adequate protection can collapse suddenly, especially after rain, leaving no time to escape.

[1] [2] [8] [12] Trenching, shoring, and ground-collapse prevention:

  • Classify soil and reassess it along the trench length and depth; unstable, wet, previously disturbed, or Type C soil requires more conservative controls.
  • Prevent surcharge loading by keeping spoil piles, materials, and equipment back from the edge and by controlling vehicle movement near the excavation.
  • Keep heavy equipment away from trench edges and use warning systems where mobile equipment operates near the excavation.
  • Control water aggressively: stop work if water is accumulating unless effective pumping and protective measures are in place under competent-person oversight.
  • Inspect for cracks, sloughing, seepage, vibration, adjacent structure instability, and weather effects; remove workers immediately if any sign of instability appears.
  • Where shielding is used, remember trench boxes protect workers inside the box but do not by themselves shore trench walls unless installed and backfilled as designed; workers must not remain in the box while it is being moved.

[1] [5] [4] [16] [10] Underground utility detection and protection:

  • Before digging, determine the approximate location of all underground installations, including sewer, telephone, fuel, electric, and water lines.
  • Use the local one-call system such as 811/Call Before You Dig or Dig Safe, and verify utilities are marked before excavation begins.
  • Support, isolate, de-energize, or otherwise protect exposed utilities as needed before employees enter the excavation.
  • Include utility strikes, gas release, electrocution, explosion, sewer exposure, and service interruption in the risk assessment, and establish emergency contact numbers for utility owners.

[7] [5] [14] Hazardous atmosphere monitoring:

  • Test for atmospheric hazards in trenches more than 4 feet deep and in any excavation where oxygen deficiency, toxic gases, vapors, exhaust, sewer gas, or natural gas may be present.
  • Monitor before entry and during the work when conditions can change, especially near sewers, gas lines, contaminated ground, or public vehicular traffic.
  • If a hazardous atmosphere exists or may exist, implement atmospheric testing, ventilation or other controls, and emergency rescue procedures and equipment; where the excavation meets confined-space criteria, apply the confined-space entry permit process.
  • Do not allow workers to enter until the atmosphere is verified safe and continuously managed as required.

[8] [5] [9] [11] Access, egress, spoil management, and site controls:

  • Provide ladders, stairs, ramps, or other safe means of egress in excavations 4 feet or deeper, located so no worker travels more than 25 feet laterally.
  • Ensure ladders are secured and extend adequately above the landing where used.
  • Keep spoil piles, materials, and equipment at least 2 feet from the edge, and place spoil so runoff drains away and material cannot slide back into the excavation.
  • Install barriers, guardrails, stop blocks, fencing, signage, and traffic controls where there is risk of falls, public exposure, or vehicle intrusion.
  • Prohibit work under suspended loads and control lifting operations around the excavation.

[1] [16] [3] [5] PPE, permit-to-work, and emergency rescue planning:

  • Minimum PPE should normally include hard hats, safety footwear, high-visibility clothing where traffic or mobile plant is present, and any additional PPE identified by the risk assessment such as gloves, eye protection, hearing protection, or respiratory protection.
  • Use an excavation permit-to-work or daily trenching log to document utility clearance, soil classification, trench dimensions, protective system, atmospheric hazards, water conditions, inspections, training, and authorization to proceed.
  • Where hazardous atmospheres, sewer/gas exposure, confined-space conditions, or unusual risks exist, require a formal permit before entry.
  • Prepare a site-specific emergency rescue plan covering collapse response, atmospheric emergency response, utility strike response, water ingress, communication, emergency contacts, rescue equipment, first aid, and how to summon external rescue services.
  • Do not rely on improvised coworker entry after a collapse; the plan should prioritize immediate scene control, emergency notification, atmospheric hazard control, and rescue by properly equipped personnel.

[5] [15] [13] [11] For OSHA-aligned compliance, your excavation procedure should at minimum require: pre-job planning; utility locating; soil classification; competent-person inspections; protective systems for trenches meeting the depth/hazard thresholds; safe access/egress; spoil and equipment setback; atmospheric testing where required; water control; traffic and fall protection; worker training; and documented daily inspections. A practical permit-to-work should stop entry whenever protection is missing, water is accumulating, atmospheric conditions are unsafe, utilities are not cleared, or the competent person identifies changing conditions that could cause collapse. [7] [6] [12]

16 source record(s)

Sources used for this answer

[1] Trenching and Excavation Safety Flyer

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# Trench and Excavation Safety Trench collapses, or cave-ins, are the leading hazard in excavation work. Safe trenching helps prevent falls, falling loads, hazardous atmospheres, and incidents involving mobile equipment. ## Trench Safety Measures Trenches 5 feet or deeper require a protective system unless dug in stable rock. For trenches less than 5 feet, a competent person must decide if protection is needed. Trenches 20 feet or deeper must have a protective system designed or approved by a registered professional engineer, as required by OSHA 1926.652(b) and (c). ## Competent Person Before workers enter a trench, a competent person must inspect it daily and after any condition changes to ensure safety. This person is trained to identify hazards, determine soil types, select protective systems, and has the authority to correct issues immediately. ## Access and Egress • Keep heavy equipment and spoils at least 2 feet from trench edges - Locate underground utilities before digging • Test for atmospheric hazards in trenches over 4 feet deep • Inspect trenches daily, at the start of each shift, after storms, and after conditions change • Never work under suspended loads - Wear high visibility clothing when near traffic # Protective Systems • Benching: a method of protecting workers from cave-ins by cutting the sides of an excavation into horizontal steps. Benching is not allowed in Type C soil. • Sloping: involves cutting back the trench wall at an angle inclined away from excavation. • Shoring: requires installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins. • Shielding: protects workers by using trench boxes or supports to prevent cave-ins. Designing these systems can be complex, as factors like soil type, trench depth, moisture, weather, nearby loads, and site activity must all be considered. OSHA standards require that employers provide workplaces free of recognized hazards. The employer must compl

[2] Toolbox Talk: Excavations and Trenches

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# EXCAVATIONS AND TRENCHES WAC [redacted identifier] defines an excavation as "Any person-made cut, cavity, trench, or depression in the earth's surface, formed by earth removal." A trench is "A narrow excavation in relation to its length made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet. If forms or other structures are installed or constructed in an excavation so as to reduce the dimension measured from the forms or structure to the side of the excavation to 15 feet (4.6 m) or less (measured at the bottom of the excavation), the excavation is also considered to be a trench." One cubic yard of soil can weigh up to 3000 pounds - approximately the weight of a small car. The fatality rate for excavation work is 112% higher than the rate for general construction, according to data from the Occupational Safety and Health Administration (OSHA). The agency lists "employee injury from collapse" as the primary hazard of excavation work and includes "no protective system" among the leading causes of worker injuries. ## EXCAVATION AND TRENCHING HAZARDS Trenching and excavation work presents serious hazards to all workers involved. Cave-ins pose the most significant risk and are more likely than other excavation- related incidents to result in worker fatalities. One cubic yard of soil can weigh as much as a car. • Collapse of soils and materials (cave-in) due to lack of, inadequate, or weak protective systems • The striking or damaging of underground utility services • Persons falling into excavations due to a lack of barriers or inadequate fencing • Asphyxiation from toxic gases which have collected in the excavation/trench • Spoil (soil from excavation/trench) or materials/equipment being placed too close to the sides of the excavation/trench, which then become overloaded and collapse • Failure to check and maintain shoring, particularly after incle

[3] Daily Trenching Log

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<table><tr><th>DATE: SIGNATURE:</th></tr><tr><td>WEATHER: PROJECT:</td></tr><tr><td>Was Dig Safe contacted: Yes No Utilities are located and marked: Yes No</td></tr><tr><td>Protective system: Trench shield (box) Wood shoring Sloping Other</td></tr><tr><td>Purpose of trenching: Drainage Water Sewer Gas Other</td></tr><tr><td>Were visual soil tests made: Yes No If yes, what type?</td></tr><tr><td>Were manual soil tests made: Yes No If yes, what type?</td></tr><tr><td>Type of soil: Stable Rock Type A Type B Type C</td></tr><tr><td>Surface encumbrances: Yes No If yes, what type?</td></tr><tr><td>Water conditions: Wet Dry Submerged</td></tr><tr><td>Possible hazardous atmosphere exists: Yes No (If yes, follow confined space entry procedures policy; complete Confined Space Entry Permit; monitor for toxic gas(es)).</td></tr><tr><td>Is trenching or excavation exposed to public vehicular traffic (exhaust emission): Yes No (If yes, refer to confined space entry procedures; complete Confined Space Entry Permit; monitor for toxic gas(es)).</td></tr><tr><td></td></tr><tr><td>Measurements of trench: Depth Length Width Is ladder within 25 feet of all workers: Yes No</td></tr><tr><td>Is excavated material stored two feet or more from edge of excavation: Yes No</td></tr><tr><td>Are employees exposed to public vehicular traffic: Yes No (If yes, warning vests required)</td></tr><tr><td>Are other utilities protected: Yes No (Water, sewer, gas or other structures)</td></tr><tr><td>Are sewer or natural gas lines exposed: Yes No (If yes, refer to confined space entry procedures policy; complete Confined Space Entry Permit; monitor for toxic gas(es)).</td></tr><tr><td>Periodic inspection: Yes No</td></tr><tr><td>Are employees trained in excavating: Yes No</td></tr><tr><td>Were employees briefed on hazards of this job: Yes No</td></tr></table>

[4] Trench Hazard Alert

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TENSIN MASSACHUSETTS DEPARTMENT OF LABOR STANDARDS # Trench Hazard Alert MASSsafety Works! Workplace Safety is No Accident Every year, workers are killed or seriously injured conducting work in trenches, including utility repair, utility inspections, and construction. Trenches are recognized by OSHA as one of the most hazardous construction work conditions, with a fatality rate more than double that for construction work overall. ## Requirements for Trench Work • Protect workers from soil cave-ins in all trenches 5' or deeper, and in shallower trenches where a cave-in hazard exists. Do this by supporting the walls with shoring, shielding workers with trench boxes, or sloping the walls back wide enough, in accordance with the OSHA Excavation Standard. • Provide ladders to workers in trenches 4' or deeper. • Underground utilities must be identified and supported. Call Dig Safe at 1-(888) 344-7233. • Ensure that workers wear high visibility clothing when exposed to vehicle traffic, and use appropriate work zone signage and traffic channeling set-ups. . Spoils must be kept back a minimum of 2' from the trench edge. Keep equipment and heavy material as far back from the trench edge as possible. • Stabilize undermined adjacent structures. • Protect employees from water accumulation by pumping out ground or utility water, and preventing drainage or other water from entering the trench. • Do not allow employees to work under suspended or raised loads or materials. • Conduct pre-job planning and inspections of trench worksites. A competent person must inspect each trench worksite, including the soil protective system, prior to the start of work, and again if there is a hazard-increasing change in conditions such as a rainstorm. Unsafe trenches are dangerous! Trenches more than 20 feet in depth must be designed by a registered professional engineer. ## Workers in trenches face other significant hazards in addition to cave-in of the soil walls, including: .

[5] Trenching and Excavation Safety Fact Sheet

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# Trenching and excavation safety (cont.) ## General trenching and excavation rules (cont.) • Test for atmospheric hazards, such as low oxygen, hazardous fumes and toxic gases when greater than four feet deep. • Inspect trenches at the start of each shift and following a rainstorm or other water intrusion. • Do not work underneath suspended or raised loads and materials. • Inspect trenches after any occurrence that could have changed conditions in the trench. • Ensure personnel wear high-visibility or other suitable clothing when exposed to vehicular traffic or mobile earth-moving equipment. ## Protective systems There are different types of protective systems – sloping, shoring and shielding. <table><tr><th>Type of protective system</th><th></th><th>Illustration of system</th></tr><tr><td>Sloping involves cutting back the trench wall at an angle inclined away from the excavation.</td><td>20 MAX</td><td></td></tr><tr><td>Shoring requires installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins.</td><td></td><td></td></tr><tr><td>Shielding protects workers by using trench boxes or other types of supports to prevent soil cave-ins. Designing a protective system can be complex because many factors must be considered: soil classification; depth of cut; water content of soil; changes caused by weather or climate; surcharge loads (spoil, other materials to be used in the trench); and other operations in the vicinity.</td><td></td><td></td></tr></table> ## More information To learn more about excavation safety, view the standards at osha.gov. Revised March 2025

[6] Trenching and Excavation Safety

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# What are the soil classification categories? (cont.) ## Why is preplanning important to excavation work? (cont.) work starts to correct mistakes in shoring or sloping slows down the operation, adds to the cost of the project, and makes a cave-in or other excavation failure more likely. ## What safety factors should be considered when bidding on a job? Before preparing a bid, employers should know as much as possible about the jobsite and the materials they will need to have on hand to perform the work safely and in compliance with OSHA standards. A safety checklist may prove helpful when employers are considering new projects. Factors to consider may include: ■Traffic ■ Proximity and physical condition of nearby structures ■Soil classification ■Surface and ground water ■Location of the water table ■ Overhead and underground utilities ■Weather ■Quantity of shoring or protective systems that may be required ■Fall protection needs ■Number of ladders that may be needed ■ Other equipment needs. Employers can gather the information they need through jobsite studies, observations, test borings for soil type or conditions, and consultations with local officials and utility companies. This information will help employers determine the amount, kind, and cost of safety equipment they will need to perform the work safely. How can employers avoid hitting underground utility lines and pipes during excavation work? Before starting work, the Excavation standards require employers to do the following: ■Determine the approximate location(s) of utility installations— including sewer, telephone, fuel, electric, and water lines. One common industry practice is to call 811, the "Call Before You Dig" number, to establish the location of any underground utility installations in the work area. Occupational Safety and Health Administration 4

[7] TOGETHER WITH TOSHA newsletter: Trench Safety

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# Trench Safety: Protecting Lives Below Ground "renches, vital for construction and Trenches, vital for constructioquickly become death traps if safety measures are ignored. Trench collapses, falling objects, and hazardous atmospheres pose grave risks. Hence, ensuring trench safety is paramount. Precautions like shoring, sloping, and trench boxes are essential to prevent cave-ins. Adequate training and supervision are vital to equipping workers with knowledge to identify hazards and respond swiftly. Regular inspections, especially after rainfall, can detect unstable conditions. Protective measures such as barricades, helmets, and harnesses further reduce risks. By prioritizing trench safety, lives are safeguarded, accidents are minimized, and productivity flourishes. Remember, when it comes to trenches, safety must always be at the forefront. ## Site Assessment Questions from OSHA's Technical Manual: During first and subsequent visits to a construction or facility maintenance location, the site's safety officer or other competent person may find the following questions useful. Is the cut, cavity, or depression a trench or an excavation? - Is the cut, cavity, or depression more than 4 ft (1.2 m) in depth? - Is there water in the cut, cavity, or depression? - Are there adequate means of access and egress? - Are there any surface encumbrances? - Is there exposure to vehicular traffic? - Are adjacent structures stabilized? - Does the mobile equipment have a warning system? Is a competent person in charge of the operation? Is equipment operating in or around the cut, cavity, or depression? Are procedures required to monitor, test, and control hazardous atmospheres? Does a competent person determine soil type? Was a soil testing device used to determine soil type? Is the soil placed 2 ft (0.6 m) or more from the edge of the cut, cavity, or depression? Is the depth 20 ft (6.1 m) or more for the cut, cavity, or depression? Has a registered professional eng

[8] Trenching and Excavation

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# Trenching and Excavation (cont.) ## Temporary protective structure (cont.) - Trench Boxes are commonly used in open areas that are away from utilities, roadways, and foundations. Trench boxes can be used to protect workers in cases of cave-ins, but not to shore up or support trench walls. They can support trench walls if the space between the box and the trench wall is backfilled with soil and compacted properly. Otherwise, a cave-in or collapse may cause the trench box to tilt or turn over. Workers should not be present in the box when it has to be moved. - Other: In some cases, the trench or excavation walls are made of rock but are not entirely stable. Support the walls by using rock bolts, wire mesh, or a method that provides equivalent support. ## What should NOT be done during an excavation? - Do not enter an unprotected trench deeper than 1.2 metres (4 feet), or as specified in the legislation. - Do not start digging before locating and de-energizing the buried services. - Do not enter a trench before testing the air for hazardous gasses and vapours, or the lack of oxygen. - Do not place the sections of pipes, piles of spoil, unused tools, and timber, and other materials within 1 metre from the trench's edge. - Do not rely on natural freezing to act as a method of soil stabilization. - Do not work under suspended or raised loads and materials. - Do not stand behind a backing vehicle. ## What can be included in a trenching and excavation inspection checklist? The following are some points to consider. Each circumstance will be different, so be sure to adapt the questions to suit your situation. ## Underground or Utility Services - Know the contact numbers? - Located, identified and informed respective parties? - Grounded, isolated, de-energized, or protected from unplanned release? ## Housekeeping Trenching and Excavation CCOHS

[9] Excavation Safety Checklist

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# Excavation Safety Checklist To be completed by a Competent Person <table><tr><th colspan="3">Date &amp; Time:</th><th colspan="5">Competent Person:</th></tr><tr><td colspan="3">Jobsite:</td><td colspan="5">Signature:</td></tr><tr><td colspan="8">Weather Conditions:</td></tr><tr><td>Purpose of Trenching:</td><td> Drainage</td><td>Water</td><td></td><td>Sewer</td><td></td><td>Gas</td><td>Other:</td></tr><tr><td colspan="8">Measurements of Trench:</td></tr><tr><td>Soil Classification:</td><td>Stable Rock</td><td colspan="3"> Type A Type B</td><td colspan="2"> Type C</td><td>Other:</td></tr><tr><td>Protective System:</td><td> Trench Shield/Box</td><td></td><td colspan="3">Wood Shoring</td><td> Sloping</td><td>Other:</td></tr><tr><td colspan="3">General Inspection of Jobsite</td><td>Yes</td><td>No</td><td></td><td>N/A</td><td>Comments</td></tr><tr><td colspan="3">1. Excavations, adjacent areas and protective systems inspected daily before start of work?</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td colspan="3">2. Is someone on site authorized to remove employees from excavation immediately?</td><td>ப</td><td></td><td></td><td>□□□</td><td></td></tr><tr><td colspan="3">3. Have surface encumbrances been removed or supported?</td><td>ப</td><td></td><td></td><td></td><td></td></tr><tr><td colspan="3">4. Are employees protected from loose rock or soil that could pose a hazard by falling or rolling into excavation?</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td colspan="3">5. Are hard hats worn by all employees?</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td colspan="3">6. Do spoils, materials, and equipment sit back at least two feet from the edge of excavation?</td><td>ㅁㅁㅁㅁ</td><td></td><td></td><td></td><td></td></tr><tr><td colspan="3">7. Are barriers provided at all remotely location excavations, wells, pits, shafts, etc..?</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td colspan="3">8. Are walkways and bridges

[10] Trenching & Excavation - Special Emphasis Program

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# Tennessee OSHA's Special Emphasis Program on Trenching & Excavation Because trenching and excavation collapse is deadly and often involves multiple victims, Tennessee OSHA has established a special emphasis program to focus attention and resources on these hazards. It is impossible to predict when an excavation or trench will collapse. The sudden collapse of the walls makes escape almost impossible. The only way to prevent collapse is to slope or shore the walls or install a trench shield and follow the TOSHA trenching and excavation standards contained in 29 CFR 1926 Subpart P. Under this special emphasis program, all TOSHA compliance and consultative services personnel will be on the lookout for trenching or excavation work sites. Personal observation, reports of imminent danger, fatality/catastrophe reports, safety and health agency referrals, employee complaints, and media reports are also used to locate trenching and excavation work. Each occurrence is handled with an appropriate intervention by TOSHA. ## Hazards on the Excavation Site Excavation workers are exposed to many hazards, but the chief hazard is cave-in. TOSHA requires that all employees exposed to potential cave-ins be protected by sloping or benching the sides of the excavation, shoring the sides of the excavation, or placing a shield between the sides and the work area. In addition to cave-in hazards, workers must also be protected from adjacent utility lines, exposure to vehicular traffic, falling loads, hazardous atmospheres, and fall hazards. Utility lines such as gas, electrical, sewer, and water must be located and supported prior to placing employees in an excavation. Employees working in, or near, roadways must wear high visibility vests. Workers are not to work beneath suspended loads, and walkways crossing excavations must be equipped with guardrails. Precautions, including atmospheric testing and emergency rescue procedures and equipment, must be taken when workers enter excavat

[11] FATALITY NARRATIVE: Contractor and Laborer Buried in Trench Collapse

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WASHINGTON State FACE Program Fatality Assessment & Control Evaluation # CONSTRUCTION FATALITY NARRATIVE FACE INCIDENT FACTS ## Contractor and Laborer Buried in Trench Collapse REPORT #: 71-240-2023 ## SUMMARY A 66-year-old contractor and a 32-year-old laborer died when the trench they were working in collapsed, burying them. The contractor and three employees had been working at a residence for a week to replace a sewer line. The contractor was the competent person on the site. To replace the sewer line they used an excavator to dig a trench that was 26-feet long and 24-feet deep. It was 24-feet wide at the top and 8-feet wide at the bottom. The sides of the trench were steep and nearly vertical. They dug the trench in unstable Type C soil and did not use protective systems such as shoring, shields, trench boxes or sloping and benching of the sides. The day before the incident, the trench collapsed after a rainstorm. REPORT DATE: May 29, 2023 INCIDENT DATE: July 4, 2022 WORKERS: 66 and 32 years old ## INDUSTRY: New Single-Family Housing Construction ## OCCUPATIONS: Contractor and laborer This narrative was developed to alert employers and workers of a tragic incident and is based on preliminary data ONLY and does not represent final determinations regarding the nature of the incident or the cause of the injury. Developed by WA State Fatality Assessment and Control Evaluation (WA FACE) Program and the Division of Occupational Safety and Health (DOSH), WA State Dept. of Labor & Industries. The WA FACE Program is supported in part by a grant from the National Institute for Occupational Safety and Health (NIOSH grant# 5U600H008487). For more information visit www.lni.wa.gov/safety-health/safety-research/ongoing-projects/work-related-fatalities-face. SCENE: Residence ## EVENT TYPE: Following the incident, investigators found: Trench collapse • Trench protection (shoring, shielding, benching, and sloping) was not used. • There was some shoring equi

[12] Trenching and Excavation

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# Trenching and Excavation (cont.) ## What should occur before beginning an excavation? (cont.) - Check areas near the site for potential hazards and sources that can impact the stability of the soil. Be aware that nearby vehicles and equipment can cause the soil to vibrate and then collapse. - Determine if nearby buildings or structures and their foundations may put pressure on the soil and affect the walls of the trench. - Test for hazardous gas, vapours, and dust before entering. Test for oxygen levels in the space before entering, and during the work as required. - Plan appropriate organization of the work site, and good housekeeping practices including moving debris and excavated soil far enough away from the excavation site. - Remove water from the excavation. - Protect workers from falling into the excavation. - Identify appropriate personal protective equipment including high visibility apparel for vehicular traffic and make sure every worker wears them as required. - Have a worker above ground when a worker is working in the trench to warn those in the trench of danger and to provide emergency help. - Determine if the trench is considered a confined space If so, do not allow workers to enter the trench until the requirements of the organization's confined space program are met, including entry permits and training. - Prepare work permits for work in confined spaces, as appropriate. - Have a means of exit provided from the inside of the trench, usually no more than 8m (25 ft) away from any worker in the trench. - Plan for adverse weather conditions (e.g. hot or cold environments, storms, etc.). - Prepare an emergency plan and rescue procedures. - Keep first aid equipment at the site. - Educate and train workers about all existing and potential hazards and risks and appropriate safety measures. ## What factors determine what is the appropriate protective system to use? In general, trenches that are 1.2 metres (4 feet) deep or great

[13] Trenching and Excavation

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# Trenching and Excavation (cont.) ## What are the hazards associated with trenching and excavation? (cont.) - Contact with buried service lines such as electrical, natural gas, water, sewage, telecommunications, etc. - Contact with overhead electrical lines. - Slips, trips and falls as workers climb on and off equipment, or from inappropriate access and egress methods. - Being struck by moving machinery, or by falling or flying objects. - Hazards related to materials handling (e.g., lifting, struck by, crushed between, etc.). ## What is meant by soil types? Definitions of soil types vary by jurisdiction in Canada. In addition, some jurisdictions have not defined soil types, but do require preventative measures when an excavation reaches a certain depth or proportion. When a soil type is defined, the purpose is to try to identify or predict the potential for the soil to move and cause a collapse while the work is being done. Soil types typically use a scale of 1 to 4 where 1 is hard and dense to 4 which is loose, soft, wet or muddy soil, or a scale of A to C where A is hard and solid, and C is soft, sandy, filled or loose. The soil type is determined by the characteristics of the soil's consistency, ease of removal, appearance, ability to excavate with hand tools vs. machine, water seepage, whether the soil has been excavated before, etc. ## What should occur before beginning an excavation? The employer or supervisor is responsible for the work, and must take the necessary steps to identify all the hazards and risks before beginning any work. These steps include to: - Identify the soil type(s) related to the excavation or trench you are going to dig. Soil properties often vary widely within a single trench (e.g., the soil type changes from top to bottom and along the length of a trench). - Look for the legislative requirements that apply in your jurisdiction and the type of protective measures to be taken. - Locate all buried services. Contact t

[14] Trenching and Excavation Safety Fact Sheet

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OSHA DEPARTMENT OF LABOR AND INDUSTRY # Fact sheet # Trenching and excavation safety From 2014 through 2019, four Minnesota workers died in a trench, excavation or ground collapse. Cave-ins pose the greatest risk and are much more likely than other excavation-related accidents to result in worker fatalities. Minnesota law requires employers to provide a workplace free of recognized hazards that may cause serious injury or death. This includes the trenching and excavation requirements of 29 CFR 1926.651 and 1926.652. An excavation is any man-made cut, cavity, trench or depression in an earth surface, formed by earth removal. A trench - or a trench excavation - is a narrow excavation (in relation to its length) made below the surface of the ground; in general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet. ## Dangers of trenching and excavation In addition to cave-ins, other potential hazards include falls, falling loads, hazardous atmospheres and incidents involving mobile equipment. Two cubic yards of soil can weigh about 6,000 pounds or as much as a small car. An unprotected trench is an early grave. Do not enter an unprotected trench. ## Trench safety measures Trenches five feet deep or greater require a protective system unless the excavation is made entirely in stable rock. If the trench is fewer than five feet deep, a competent person may determine a protective system is not required. Trenches 20 feet deep or greater require that the protective system be designed by a registered professional engineer or be based on tabulated data prepared and/or approved by a registered professional engineer in accordance with 1926.652(b) and (c). ## Competent person OSHA standards require employers ensure trenches - before worker entry - are inspected by a competent person daily and as conditions change, to ensure elimination of excavation hazards. A competent person is an individual: who is capab

[15] Excavation Checklist and Trenching Log

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# SAMPLE - Daily Trenching Log # DAILY TRENCHING LOG DATE: <empty> SIGNATURE: <empty> WEATHER: <empty> PROJECT: <empty> Was One Call System contacted: Yes [ ] No [ ] Protective system: Trench shield (box) [ ] Wood shoring [ ] Sloping [ ] Other [ ] Purpose of trenching: Drainage [ ] Water [ ] Sewer [ ] Gas [ ] Other [ ] Were visual soil tests made: Yes [ ] No [ ] If yes, what type?: <empty> Were manual soil tests made: Yes [ ] No [ ] If yes, what type?: <empty> Type of soil: Stable Rock [ ] Type A [ ] Type B [ ] Type C [ ] Surface encumbrances: Yes [ ] No [ ] If yes, what type?: <empty> Water conditions: Wet [ ] Dry [ ] Submerged [ ] Hazardous atmosphere exists: Yes [ ] No [ ] (If yes, follow confined space entry procedures policy; complete Confined Space Entry Permit; monitor for toxic gas(es)) Is trenching or excavation exposed to public vehicular traffic (exhaust emission): Yes [ ] No [ ] (If yes, refer to confined space entry procedures; complete Confined Space Entry Permit; monitor for toxic gas(es)) Measurements of trench: Depth: <empty> Length: <empty> Width: <empty> Is ladder within 25 feet of all workers: Yes [ ] No [ ] Is excavated material stored two feet or more from edge of excavation: Yes [ ] No [ ] Are employees exposed to public vehicular traffic: Yes [ ] No [ ] (If yes, warning vests required) Are other utilities protected: Yes [ ] No [ ] (Water, sewer, gas or other structures) Are sewer or natural gas lines exposed: Yes [ ] No [ ] (If yes, refer to confined space entry procedures policy; complete Confined Space Entry Permit; monitor for toxic gas(es)) Periodic inspection: Yes [ ] No [ ] Did employees receive training in excavating: Yes [ ] No [ ]

[16] Oregon OSHA Technical Manual, Section V: Construction Operations, Chapter 2: Excavations: Hazard Recognition in Trenching and Shoring

Page 20

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# VIII. Sloping and Benching (cont.) ## A. Temporary Spoil (cont.) Spoil should be placed so that it channels rainwater and other run-off water away from the excavation. Spoil should be placed so that it cannot accidently run, slide, or fall back into the excavation. Figure V:2-16. Temporary Spoil Temporary Spoil -2 feet Minimum- ## B. Permanent Spoil Permanent spoil should be placed some distance from the excavation. Permanent spoil is often created where underpasses are built or utilities are buried. The improper placement of permanent spoil, i.e., insufficient distance from the working excavation, can cause an excavation to be out of compliance with the horizontal to vertical ratio requirement for a particular excavation. This can usually be determined through visual observation. Permanent spoil can change undisturbed soil to disturbed soil and dramatically alter slope requirements. ## X. Special Health and Safety Considerations ## A. Competent Person The designated competent person should have and be able to demonstrate the following: • Training, experience, and knowledge of: - soil analysis, - use of protective systems, and - requirements of 29 CFR Part 1926 Subpart P. • Ability to detect: - conditions that could result in cave-ins, - failures in protective systems, - hazardous atmospheres, and - other hazards including those associated with confined spaces. Section V/Chapter 2 - Page 20

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