Questions of Competence

At the root of nearly every trenching and excavation accident is a failure to comply with safety regulations and good practices.

• By Fred Elliott
• Jun 01, 2003

IN one important sense, trenching and excavation accidents are unlike other construction accidents: The cause of nearly every trenching and excavation accident is a failure to comply with safety regulations and good practices. This may be true of any construction accident, but it is overwhelmingly true of cave-ins and other excavation accidents.

Poorly trained workers and supervisors may be the main factor responsible for these failures. Excavations often are completed quickly, without proper assessment of the soils, water table, underground or overhead utilities, and other conditions involved. Operations of this type tend to ignore egress ladders, shields, or trench boxes-- or they use the protective devices improperly. They may not take time to construct sloping or benching systems when necessary.

These are signs that a competent person is not on the scene, as required for excavations 5 feet or more deep that are entered by workers. (At 4 feet, egress ladders are mandatory and measurement of hazardous atmospheres required, if the competent person believes employees entering the excavation could be exposed to a hazardous atmosphere.) As the Occupational Safety and Health Administration defines the term, a competent person "is capable of identifying existing and predictable hazards in the surroundings, or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them."

At 29 CFR 1926.651(k)(1), OSHA's construction safety regulations mandate daily inspections of excavations, the adjacent areas, and protective systems by a competent person who must look "for evidence of a situation that could result in possible cave-ins, indications of failure of protective systems, hazardous atmospheres, or other hazardous conditions." Inspections are required before work begins and as needed throughout each work shift. Inspections also must be conducted after a rainstorm, snowstorm, earthquake, or "other hazard increasing occurrence" when employee exposure can be reasonably anticipated.

If the competent person finds such evidence, employees must be removed from the hazardous area until steps have been taken to ensure their safety.

National Emphasis, Six-Figure Fines
OSHA has a national emphasis program on trenching and excavation under way. Six-figure penalties have resulted from allowing crews to work in unprotected trenches. When a Florida contractor was fined about $125,000 earlier this year, OSHA's Tampa office cited the violation of allowing unprotected workers to lay concrete pipe for a storm water drain in a 12-foot-deep trench. Placing spoil piles too close to the excavation also was cited.

"Trenching accidents are a major cause of job-related injuries and fatalities, particularly in the Southeast," Labor Secretary Elaine Chao said at the time. Les Groves, the agency's Tampa area director, spelled out the kind of practices that endanger workers all too frequently--and, in this case, accounted for a large fine: "The employer allowed employees to work in hazardous circumstances even though its safety and health plan addressed trench safety procedures, the foreman and superintendent on the job had received 'competent person' training for trench excavations, and a trench box was available only one-half mile from the job site."

Toolbox Meetings
Safety experts advise conducting daily toolbox or tailgate safety meetings before workers dig or enter a trench. It's a good idea to include a personal story about this type of work and to remind employees that one cubic yard of soil typically weighs more than 2,000 pounds. Tell them they simply cannot outrun a cave-in, protect themselves when a trench wall collapses, or dig themselves out.

Other points to address:

• Keep spoil piles at least 2 feet from the edge of the excavation.
• Underground utility lines should be marked ahead of time. Be sure you do not interfere with electrical, gas, telephone, water, or sewer lines.
• Don't work in accumulated water.
• Don't work after rain or snow until a competent person has inspected the trench and declared it safe to enter.
• If the trench is more than 4 feet deep, place egress ladders so all workers can reach them after no more than 25 feet of lateral travel.
• Never work beneath a suspended load.
• If employees or equipment must cross a trench 6 feet or more deep, a walkway with guardrails is required.

This article originally appeared in the June 2003 issue of Occupational Health & Safety.