The Trench That Was 'Only for a Minute'
On a Grade 9 site, a groundworks gang is installing a 1.2 m deep drainage run alongside a live pedestrian route. The excavation has no trench support and no edge protection on the pedestrian side. The gang leader says the trench will be open 'only for a minute' while a pipe is laid, and that the ground is 'good clay'. Two workers are in the trench. A delivery lorry is waiting and the site manager is under pressure to keep the concrete pour on schedule. You are the safety adviser doing a walk-round.
1. Identify the breaches and the immediate actions required.
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Breaches:
- Unsupported excavation at 1.2 m in ground that may still spall; 'good clay' is an assumption, not an assessment.
- No edge protection on the pedestrian side, exposing the public to a fall into the trench.
- Two workers in an unprotected trench - a collapse would be fatal.
- No segregation of the live pedestrian route from the works.
Immediate actions (stop-work authority):
- Order the workers out of the trench now.
- Stop the operation and barricade/cone the area; divert pedestrians.
- Do not restart until the excavation is supported or battered back and edge protection is in place.
- Record the stop, notify the site manager and principal contractor.
'Only for a minute' is not a control. The exposure is the same whether the trench is open for one minute or one day.
2. The site manager says stopping will delay the pour and cost money. How do you respond, and what do you document?
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Response: the cost of the delay is not comparable to a fatality or serious injury, and the law does not permit the trade-off. A collapse in clay can occur without warning; two people in an unsupported 1.2 m trench is an unacceptable risk regardless of schedule pressure.
Offer a practical route: support or batter the trench, install edge protection and pedestrian diversion, then resume - likely hours, not days, if the gang is redirected to another run meanwhile.
Document:
- Time, location and description of the breach.
- Names of those in the trench and the gang leader's statement.
- The stop-work instruction and to whom given.
- Photographs and a sketch of the pedestrian route.
- The restart conditions and who confirmed them.
Escalate if the stop is overridden; a written record protects you and the workers.