Questions of Competence

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

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.

Guide for Daily Inspection of Trenches and Excavations

Project:

Date:

Weather:

Soil Type:

Trench Depth:

Length:

Width:

Type of Protective System:

Excavation

Yes

No

N/A

Excavations and Protective Systems inspected by Competent Person daily, before start of work.

Yes

No

N/A

Competent Person has authority to remove workers from excavation immediately.

Yes

No

N/A

Surface encumbrances supported or removed.

Yes

No

N/A

Employees protected from loose rock or soil.

Yes

No

N/A

Hard hats worn by all employees.

Yes

No

N/A

Spoils, materials, and equipment set back a minimum of 2 feet from edge of excavation.

Yes

No

N/A

Barriers provided at all remote excavations, wells, pits, shafts, etc.

Yes

No

N/A

Walkways and bridges over excavations 6 feet or more in depth equipped with guardrails.

Yes

No

N/A

Warning vests or other highly visible PPE provided and worn by all employees exposed to vehicular traffic.

Yes

No

N/A

Employees prohibited from working or walking under suspended loads.

Yes

No

N/A

Employees prohibited from working on faces of sloped or benched excavations above other employees.

Yes

No

N/A

Warning system established and used when mobile equipment is operating near edge of excavation.

 Utilities

Yes

No

N/A

Utility companies contacted and/or utilities located.

Yes

No

N/A

Exact location of utilities marked when near excavation.

Yes

No

N/A

Underground installations protected, supported, or removed when excavation is open.

Wet Conditions

Yes

No

N/A

Precautions taken to protect employees from accumulation of water.

Yes

No

N/A

Water removal equipment monitored by Competent Person.

Yes

No

N/A

Surface water controlled or diverted.

Yes

No

N/A

Inspection made after each rainstorm.

Hazardous Atmosphere

Yes

No

N/A

Atmosphere tested when there is a possibility of oxygen deficiency or build-up of hazardous gases.

Yes

No

N/A

Oxygen content is between 19.5 percent and 21 percent.

Yes

No

N/A

Ventilation provided to prevent flammable gas build-up to 20 percent of lower explosive limit of the gas.

Yes

No

N/A

Testing conducted to ensure that atmosphere remains safe.

Yes

No

N/A

Emergency Response Equipment readily available where a hazardous atmosphere could or does exist.

Yes

No

N/A

Employees trained in the use of Personal Protective and Emergency Response Equipment.

Yes

No

N/A

Safety harness and lifeline individually attended when employees enter deep confined excavation.

Signature of Competent Person: ______________

Date: ___________________

SOURCE: OSHA Construction eTool, www.osha.gov/SLTC/etools/construction/trenching/excavchec.html

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

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