Safe access in and out of the trench is critical. Mainly when a cave in, injury, or other crisis could exist. Workers need to be able to getaway quickly in the event of a cave in. If the trench is 1.5M deep or more, OH&S regulations require proper access and egress for all workers every 8M. That includes ladders, stairs, or a ramp. That egress must be constructed by someone with ground disturbance training. Methods must be protected so that workings of the egress will not be obstructed in the event of an incident.