Trench Crossings
The Problem
Trenches are among the most hazardous areas on a construction site, and crossing them incorrectly can result in serious injury or even death. From slips and falls to machinery incidents, unsafe trench crossings put both workers and equipment at risk. Today, we’ll identify the key hazards, refer to WorkSafe New Zealand’s expectations around trench safety, and discuss best practices to ensure safe passage in these high-risk areas.
Identify the Hazards
Personnel Hazards:
- Slips or trips resulting in falls into the trench
- Ankle or knee injuries caused by uneven or unstable ground
- Falls from height due to missing or inadequate edge protection
- Risk of being struck by falling tools, materials, or equipment
Equipment Hazards:
- Collapse of trench edges under the weight of machinery
- Plant rollovers caused by poor ground support or improper crossing setup
- Structural failure of temporary crossing platforms or bridges
- Machinery contacting trench walls, increasing the risk of collapse
- Machinery striking workers inside the trench during operations
Safety Practices and Preventative Measures
Pedestrian Walkway Requirements:
- Ensure a minimum clear width of 500mm for safe passage and emergency egress
- Extend walkways at least 600mm past the trench edge to reduce the risk of instability
- Walkways must have firm, stable footing and be capable of supporting four times the intended load
Edge Protection (When Working Near or Over a Drop):
- Top rail: Installed at approximately 1.1 metres high and able to withstand a minimum of 900N outward force
- Mid-rail: Installed halfway between the top rail and the walking surface
- Toe boards: At least 100mm high to prevent tools or debris falling into the trench
Note: Refer to WorkSafe NZ's Good Practice Guidelines for Working at Height in New Zealand for further detail.
Vehicle and Machinery Crossings:
- Must be designed or verified by a Chartered Professional Engineer (CPEng)
- Considerations include load ratings, ground conditions, type of plant, site traffic flow, and weather exposure
- Crossings must be inspected daily to ensure structural soundness and safe operation
Implementation and Ongoing Maintenance:
- A competent person must inspect trench crossings, guardrails, and support structures daily for signs of wear, damage, or instability
- Immediate action must be taken to repair or replace any compromised components
- Surfaces should be kept clear of mud, ice, or debris to prevent slips and maintain traction
Best Practices for Risk Management:
- Planning: Position trench crossings in practical locations based on worker access, equipment movement, site layout, lighting, and weather conditions
- Training: Ensure all workers are trained in correct use of trench crossings, know how to identify hazards, and understand reporting procedures
Real-Life Case or Scenario
A construction worker slipped on a poorly maintained trench crossing and fell approximately 3 metres into the trench. The crossing lacked toe boards and edge protection, and the walking surface was worn and slippery. The worker sustained multiple injuries, leading to significant project delays. This incident could have been avoided through regular maintenance and adherence to WorkSafe New Zealand’s trench and excavation safety guidelines.
Employee Responsibilities
- Use trench crossings only as intended and always follow site-specific safety procedures.
- Inspect crossings before each use and report any signs of damage, instability, or missing components.
- Avoid shortcuts—never walk on unprotected trench edges or unstable ground.
- Wear the correct personal protective equipment (PPE), including safety boots and high-visibility gear, to reduce risk.
Employer Responsibilities
- Provide engineered trench crossings that meet WorkSafe New Zealand’s guidelines and are appropriate for the load and site conditions
- Ensure all workers are trained on the correct use of trench crossings, including hazard identification and safe work practices
- Conduct daily inspections of all trench crossings, and take immediate action to repair or replace any damaged or unsafe components
- Keep detailed records of all inspections, maintenance, and corrective actions as part of your site’s health and safety documentation
Discussion & Questions
Commitment/Action Plan
Let’s commit to inspecting all trench crossings daily and reporting any concerns immediately. Moving forward, we’ll ensure that all crossings meet OSHA’s requirements and are properly maintained to protect everyone on-site.
Wrap-Up
Safe trench crossings require planning, proper design, and constant vigilance. Every safety specification exists because someone was harmed when that standard was ignored. Let’s ensure we put safety first and prevent those kinds of incidents from happening on our site. Thank you for your attention and commitment to keeping our worksite safe.
Standards Overview
- WorkSafe New Zealand provides clear guidance on excavation and trenching safety, including how to manage trench crossings. This includes expectations for safe pedestrian access, the use of barriers or guardrails, and ensuring vehicle crossings are properly designed to prevent collapses or rollovers. Following these guidelines isn’t just a legal duty under the Health and Safety at Work Act 2015—it’s critical to protecting workers from avoidable incidents.
Disclaimer
These toolbox talks are provided for informational and educational purposes only and are not a substitute for professional legal, health and safety, or regulatory advice.
The content reflects recognised best practices and general industry standards as at the date of publication. However, it may not be applicable to all workplace environments or specific operational contexts.
It is the responsibility of the Person Conducting a Business or Undertaking (PCBU), as well as officers, workers, and other duty holders under the Health and Safety at Work Act 2015 (HSWA), to ensure compliance with all relevant laws, regulations, and WorkSafe New Zealand guidance.
The authors, presenters, and distributors of this toolbox talk disclaim all liability for any loss, damage, or injury arising from the use or reliance on the information provided. Users should seek advice from a suitably qualified health and safety professional or legal advisor for guidance tailored to their specific circumstances.
Always follow your organisation’s policies, procedures, and safe work practices to manage risks and maintain a safe and healthy workplace.
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