One of the deadliest accidents on construction sites are trench collapses. They can happen quickly and with little warning to alert those workers down inside the excavation. They become trapped and often die before rescue crews can get them to the surface.
All five sections of the trench can be vulnerable to a collapse if they become destabilized.
Safety standards for open trenches
If you are working on a job site where there are trenches, the following safety rules apply:
Workers must be protected from risks of the trench caving in when they enter, exit and work inside of the trench.
All trenches more than five feet deep have to be shored.
There shall be no excavation more than two feet beneath the bottom of the shoring system.
The spoil pile of excavated material must not be accumulated closer than two feet to the trench’s lip.
No workers may be inside of trench boxes or shields as they are moved vertically, installed or removed.
What about smaller trenches?
Even trenches of depths less than five feet can be extremely dangerous to those working in and around it. The competent person who examines the excavation may order it be shored if:
A potential collapse might occur.
There is vibration from machinery or nearby traffic.
The trench is located parallel to two feet of a road or another trench.
The trench has been open for longer than one day.
Why are trenches so hazardous?
Soil is very heavy and often the composition of the excavated material is unstable. The two conditions can combine to create a lethal situation for the workers. Rock is more stable than clay loam or cemented soil, which in turn are more stable than sandy soil that easily crumbles.
Water and wet conditions contribute to the destabilization of soil around trenches, making it crucial to closely examine the trench during inclement weather.
What happens in a collapse?
The circumstances of trench collapses vary, but a collapse of soil falling from just 10 feet can tumble down at the speed of 17 mph. That gives victims no time to react. The weight of soil is approximately 100 pounds per cubic foot. A single cubic yard of excavated soil weighs about 3,000 lbs. That is more than enough pressure to compress a victim’s chest and make breathing impossible, as their chest cannot expand to breathe in air.
Were you injured in a trench collapse?
You may be entitled to workers’ compensation benefits if you suffered injuries in a trench collapse on the job site. Learn more about your options to seek compensation by consulting a Denver workers’ compensation attorney.