Trenching is an essential part of most construction and civil projects, but it’s also one of the most hazardous. Workers face serious risks from collapses, falling materials, and unsafe working conditions inside excavations. In Australia, any trench deeper than 1.5 metres is classified as high-risk work, meaning it requires proper planning, protective systems, and strict safety measures.
Whether you’re managing a small dig or a large-scale project, understanding the hazards and knowing how to control them is the key to keeping your team safe. In this article, we’ll walk you through the main trench hazards, practical safety tips, and the essential tools you need to stay compliant and protected on-site.
Understanding trench hazards
According to Safe Work Australia’s Excavation Code of Practice, any excavation that is deeper than 1.5 metres is high-risk. The biggest risk factor with trench work is cave-ins. Cave-ins are dangerous as they often occur spontaneously, trapping workers inside and leading to serious injuries or fatalities. The following are a few risk factors that can result in cave-in, falls and gas toxicity.
Soil instability
If the soil is loose or unstable, it can collapse, causing cave-ins. The risk increases with loose or wet soil, vibrations from nearby machinery, or poor shoring practices.
Water accumulation
Rain, groundwater, or leaking pipes can weaken trench walls and make them prone to collapse. Standing water can also conceal hazards, limit footing, and make escape difficult during emergencies.
Heavy machinery and vibrations
Maintaining a safe distance from the trench is crucial, as the edges can easily collapse under pressure. Operating excavators, trucks, or loaders too close to the trench edge transmits vibrations and weight to the trench walls. The vibration alone can trigger a collapse; hence, if you are working near industries or heavy traffic, take extra precautions and ensure proper trench protection is in place.
Falls
Improper entry and exit can cause falls, resulting in injuries. Moreover proper emergency exit should be set up for high-risk excavations. Without an emergency exit plan, workers can become trapped if the trench starts to cave in.
Atmospheric hazards
Trenches can collect toxic gases, fumes, or low-oxygen air, especially in deeper or confined sections. Without proper monitoring, workers might not notice the danger until it’s too late.
7 practical tips to ensure trench safety
Keeping your crew safe in and around trenches requires planning, risk assessment, the right gear and tools, and consistent checks. Here are seven practical tips to help you create a safer worksite and stay compliant with Safe Work Australia guidelines.
1. Assess the site before you dig
Safe trench work always starts with an assessment by a competent person. This includes identifying the soil type, water table levels, nearby utilities, vibration sources and any other potential hazards or challenges. All the information is documented for record-keeping.
This information will guide your emergency plan, which is required by Safe Work Australia for all trenches deeper than 1.5 metres.
2. Plan for shoring or shielding early
Never leave trench support to chance. Decide on your shoring or shielding system before digging. The right setup, such as trench boxes or hydraulic shoring systems, keeps the walls stable and prevents collapse. Remember: the deeper the trench, the stronger the protection required.
Also read: What is shoring? Types, safety, installation and removal
3. Keep heavy machinery away from edges
Operating excavators, trucks, or loaders too close to the trench adds pressure that can destabilise the walls. To minimise the risk, keep all equipment, excavated material, and storage loads outside the “zone of influence.”
The zone of influence is the area around a trench where extra weight could affect ground stability or cause movement along the excavation face. Its range depends on soil type, moisture, and other ground conditions, which is why it should always be assessed by a competent person.
4. Regularly inspect the trench
Trench conditions can shift quickly. Inspect daily before work begins and after any event that could affect stability, such as rain, vibration, or soil drying out. In case of cracks, bulges, or seepage, stop work until a competent person confirms it’s safe to continue.
5. Provide safe access and egress
To ensure a safe and stable entry and exit in the trench, install ladders, ramps, or steps. It allows for a quick escape if the trench starts to cave in or if flooding occurs.
Check out how Legend Hire helped a civil contractor overcome access challenges with the AdjustaStair Solution
7. Communicate with the crew
Even the best safety plan will not work if your team doesn’t follow it. Conduct toolbox talks before work begins, explain escape routes, and make sure everyone knows how to use the protective systems on-site. A well-informed team is your first line of defence against accidents.
Legend Hire’s tools and equipment for trench safety
Here are three essential tools and systems that every safe excavation site should have. All the trench safety equipment is available for hire at Legend Hire.
1. Trench Boxes
Trench shields or trench boxes are protective systems that protect the workers in case of cave-ins. They’re widely used and provide a strong, stable barrier between workers and unstable soil.
Legend Hire offers a range of steel and aluminium trench boxes to suit different trench widths and depths. We also provide customised trench boxes to ensure every trench gets the appropriate protection that it needs.
Also read: How to install a trench box
2. Manhole boxes
For deeper or vertical access points, manhole boxes provide full protection while allowing safe movement for installation or inspection work.
Legend Hire’s aluminium manhole boxes are engineered for strength, durability, and compliance, ensuring crews can work safely at greater depths.
3. Access ladders and platforms
Safe access and egress are essential for the safety of the workers. Legend Hire provides a range of ladders, staircases, handrails, access ramps and access platforms. These tools make entering and exiting trenches safer and faster, reducing the risk of slips and falls. Moreover, our trench safety range includes harnesses, gas monitors and a lot more to keep your crew safe. Check out Legend Hire’s trench safety equipment for hire.
Whether you’re managing a small dig or a major excavation, having the right equipment makes all the difference. Legend Hire offers a full range of trench safety gear designed to protect your crew and keep your project on track. Our expert team can help you choose and install the right equipment for the job.
Get in touch to talk to our expert or hire our trench safety equipment.