What are ways to protect against trench cave-ins?
The Occupational Safety and Health Administration (OSHA) reports that more than two workers are killed each month nationwide in trench collapses. To minimize the potential for a collapse, OSHA identifies several methods for promoting workplace safety in trenches.
- The easiest, if there is space and the soil allows it, is to slope the embankment at a maximum of 1:1 slope, a 2:1 slope is preferred.
- Another way is to create stepped benches, this should be used with only Hydrologic Soil Groups A and B.
- Additional methods require materials to support the excavation. Items such as posts, beams, shores, or planking, and hydraulic jacks can be used to support the cut material. A trench box is a proven method of protecting workers. The box can be dragged along with the excavation to provide an uninterrupted work area.
When working around an excavated trench, keep excavation spoils and equipment at least two feet from the edge of the trench. Also, an escape path must be provided for every 25 feet of trench. This allows for a quick exit by workers in the event of a problem.
A competent worker should inspect trenches daily and whenever conditions change. OSHA defines a competent person as someone who is:
- “capable of identifying existing and predictable hazards in the surroundings, or
- working conditions that are unsanitary, hazardous, or dangerous to employees, and
- who has authorization to take prompt corrective measures to eliminate them”
Resources
OSHA Quick card: Working Safely in Trenches
Competent Person
OSHA Trenching & Excavation Safety Manual
March 2016