Excavation work is one of the most dangerous types of work, not because there are more accidents during excavation and trenching activities, but because cave-ins tend to have higher fatality rates.
On a dynamic job like an excavation, each day and periodically during the day, site conditions will change. A Competent Person must physically be on site to recognize these hazards and must have the authority to make decisions based upon the hazard.
Important Definitions
An Excavation is any man-made cut, cavity, trench or depression in an earth surface, formed by earth removal.
A Trench is a narrow excavation made below the surface of the ground. In general, the depth is greater than the width; the width of a trench (measured at the bottom) is not greater than 15 feet.
Shoring is a structure that is built or put in place to support the sides of an excavation to prevent cave-ins.
A Competent Person is one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous or dangerous to employees, and has the authority to take prompt corrective measures to eliminate them.
- They know excavation safety standards including soil classification
- They know the proper use of protective systems and trench safety equipment
- They have the authority to stop work when unsafe conditions exist
- They have documented experience and training
Why are excavations dangerous?
Excavations can have all the characteristics of a confined space. They are not meant for continuous human habitation, egress is limited and atmospheric conditions can become unsafe for workers. Dangerous gases settle at the bottom of trenches. Air quality and ventilation is another area a competent person is trained to inspect and monitor.
Excavation Hazards
Excavations are hazardous because a worker can become engulfed by collapsing soil. One cubic yard of soil can weigh as much as a mid-size pickup truck. When all this soil surrounds a worker, he or she may not be able to breathe even if not completely engulfed. Some other hazards associated with excavation work include:
- Injury or death from collapse or cave-in
- Working in or around mobile equipment
- Vibration
- Manual material handling
- Working in proximity to traffic
- Various hazards from subsurface installations and overhead lines
- Fall hazards
- Hazardous atmospheric conditions
- Electrical hazards
We're only digging a few feet, is it really that dangerous?
64% of fatalities in trenches occurred at depths of less than 10 feet. OSHA requires that all excavations and trenches over five feet deep have one of four protective systems:
- Sloping the ground
- Benching the ground
- Shoring the trench with supports such as planking or hydraulic jacks
- Shielding the trench (using a trench box)
Workers should never enter a trench that does not have a protective system installed and inspected by a competent person.
How can I bring my facility into compliance?
California employers are required to have a written and effective program for prevention injuries and illnesses, the IIPP. If excavating/trenching is one of your regular activities, you need to train your employees in the hazards at hire, when conditions change or when new hazards are recognized or introduced.
The California Excavation Standard mirrors the Federal Standard with additional requirements for subsurface Installations and a permit requirement.
How will safety training save my company money?
The initial expense of training a Competent Person and purchasing or leasing the appropriate shoring equipment for the job will far outweighs the expense of a fatality, work stoppage, investigation, CalOSHA fines, etc.
What changes may be coming?
This month's regulatory update contains information on proposed changes to the California Construction Safety orders and Tunnel Safety Orders that may tighten the requirements for air monitoring and ventilation in excavations and trenches when combustible gas engines (i.e. generators, mobile equipment) are used in or near an excavation or trench.
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| Click to view a live trench collapse. |
Notice how quickly the event occurs.
How much time does an employee have to escape?
How long does it take for coworkers to provide a means of egress?
What other Resources are Available?
This month's safety tool box includes many resources to help the safety professional educate and train workers in hazard identification and safe work practices in and around excavations.
What you can do to create a safer workplace:
- Become informed, take a class
- Study the resources attached
- Implement a training program at your facility
- Create, implement and follow safe excavation procedures for your company
The next Competent Person Excavation class offered at our Sacramento location is September 16, 2011. Our Claremont location is offering Competent Person Excavation on September 15, 2011. We are always available to come to your job site to conduct trainings as well.
To contact the Sacramento office, call (916) 366-7233 x 219 or email us at workplacesafety@safetycenter.org.
To contact the Claremont office, please call (909) 625-9650 or email gayleen@safetycenter.org.
To see a full listing of competent person excavation courses, view our class calendar on-line or visit the competent person excavation class page here.
