I recently heard a quote about evil being the product of desperation meeting opportunity. My first thought after hearing it was, “What opportunities are we creating for the highest of workplace evils – death – to occur?”
A safety-related version of the quote, “Risk is the product of unsafe work practices meeting with unsafe conditions (or vice versa).” How many chances for risk are you creating or allowing your workers to be exposed to during excavation and trenching work?
What are the Risks?
The risk of an excavation or trench collapse (cave-in) is extremely high in most digs – unless your dealing with solid rock. You may have heard it before, but it’s worth repeating – it’s not a matter of if a collapse will happen, rather it’s matter of WHEN the collapse will happen.
In addition to cave-ins, other risks include:
- Spoil piles too close to excavation’s edge
- Falling/flying objects and materials
- Equipment mishaps
- Slips, trips, and falls
- Hazardous atmospheres
- Water accumulation
Be a Better Supervisor
One of the most important aspects of your role as a supervisor is to protect your crews from harm by minimizing the opportunities for risk to occur. The first step towards doing this is to realize that every action or inaction has a consequence.
If you don’t have a plan for every excavation you increase the risk placed on your workers and others on the site. If you allow supervisors to ignore safe work practices you increase the risk. If you don’t train supervisors, competent persons, and crews on safe excavation and trenching you increase their risk of serious injury and death. If you allow anyone to enter an unprotected excavation or trench you are taking a chance those workers won’t make it home to see their families.
The second step is to train and instruct workers and supervisors that no one will enter an unprotected excavation or trench. Enforce this rule and take disciplinary action against anyone that breaks it. You could be saving someone’s life.
Let’s look at six additional steps you can take to reduce the opportunities for risk.
Get familiar with the types of protective systems available to protect workers from cave-ins. Understand what protection is best suited for the specific conditions of each excavation. Consider soil type, depth and width, and other conditions to determine the best protective system.
2. Falling Objects and Materials
- If excavated material must be placed near the excavation, ensure barricades are in place to prevent fallback.
- Heavy tarpaulins, sheeted barricades and built-up board barricades can help keep excavated material out of work areas.
- Barriers can help keep tools and workers from falling onto other workers in the excavation or trench. If the trench or excavation must stay open for a long time, barricades, fences and so forth are necessary.
- Guard the site at night with flashing lights or security fences.
- Keep workers out of the operating radius of backhoes and other equipment.
- Protect workers when installing and removing protective systems. Here are a few examples:
- Don’t allow workers in the excavation during installation or removal.
- Removal must begin at, and progress from, the bottom of the excavation.
- Backfilling must progress together with the removal of support systems from excavations.
3. Equipment Mishaps
Maintenance and Repair
- Maintain equipment safety features, such as roll over protective structures.
- Provide systematic inspection, maintenance and repair programs.
- Make sure operators and repair personnel are competent.
Traffic and Crowd-Control
- Backing alarms are required on all mobile equipment in areas where workers are at risk of being struck.
- In crowded work areas have a signaler direct traffic and warn workers of moving equipment.
- Each signaler should wear a high-visibility vest when directing traffic.
- A standard set of signals should always be used.
- The signaler must always stay in the view of drivers.
Safe Work Practices
- Require workers to use three-points of contact (and avoid jumping) when getting on or off equipment.
- Do not allow passengers to ride outside of equipment cabs.
- Workers should be warned to keep away from excavators, backhoes and similar equipment.
- When appropriate, danger zones around equipment should be barricaded or roped off to keep workers out.
- Operators should be informed before any worker enters.
- Operators should always keep workers in the danger zone in sight.
- Equipment should not be operated while workers are present.
4. Slips, Trips, and Falls
- Make sure that ladders extend at least 3 feet/1 meter above the trench wall.
- Instruct workers to hold both side rails and have one foot on a rung (three points of contact) when using a ladder.
- Keep fences and barriers far enough away from the excavation’s edge to prevent workers or bystanders from slipping or falling into the opening.
5. Hazardous Atmosphere
Know the requirements for when atmospheric testing must be done. Enforce testing and instruct workers not to enter until testing has been performed.
6. Water Accumulation
Water in an excavation can undermine the sides of the excavation and make it more difficult for workers to get out of the excavation.
- Keep workers out of excavations where water has accumulated or is accumulating unless precautions have been taken to protect the worker.
- Special support or shield systems to prevent cave-ins.
- Water removal to control water level.
- Use of harness and lifeline.