Job Hazard Analysis: Foundation excavation

A general example for this task. Your JHA should reflect your crew, equipment and site — review it with a competent person before work starts.

Steps, hazards and controls

1. 1. Plan the dig: call 811, mark utilities, and pick the protective system

   • Hitting buried gas, electric, water, or fiber linesHigh
     • Call 811 before digging and wait for all utilities to respond and mark the ground.
     • Walk the site with the competent person and check that paint and flags match the plans.
     • Hand-dig or vacuum-excavate to expose lines inside the tolerance zone before using the bucket.
   • Cave-in from wrong soil type or no protective planHigh
     • Have the competent person classify the soil (Type A, B, or C) before digging.
     • Choose sloping, benching, or a trench box rated for the depth before work starts. If in doubt, treat soil as Type C.
   • Overhead power lines in the excavator's reachHigh
     • Locate overhead lines and keep the boom at least 10 ft away from lines up to 50 kV.
     • Call the utility to de-energize or cover the lines if you can't keep clearance, and assign a dedicated spotter.

2. 2. Set up the site: barricades, traffic control, and equipment check

   • Workers or public struck by trucks and equipmentHigh
     • Set cones, fence, or barricades to keep people out of the work zone.
     • Plan one-way haul routes and use a spotter when trucks back up.
     • Wear a high-visibility Class 2 vest at all times.
   • Equipment failure from bad brakes, hydraulics, or backup alarmMedium
     • Do the pre-shift walk-around on the excavator and loader: tracks, hoses, leaks, horn, backup alarm, seat belt.
     • Tag out any machine with a defect and don't run it until repaired.

3. 3. Dig the foundation with the excavator and place spoil

   • Struck or crushed by the excavator swing or bucketHigh
     • Mark the swing radius with cones or tape and keep everyone outside it.
     • Make eye contact and get a signal from the operator before walking near the machine.
     • Never stand under a loaded bucket or near a truck being loaded.
   • Spoil pile or equipment collapsing the edgeHigh
     • Keep spoil, materials, and equipment at least 2 ft back from the edge.
     • Keep heavy equipment back from the edge or use stop logs so wheels and tracks can't roll in.
   • Loud engine noiseMedium
     • Keep cab doors and windows closed while operating.
     • Wear earplugs or earmuffs when working near running equipment.

4. 4. Install the protective system: slope, bench, or set the trench box

   • Cave-in while the protective system is going inHigh
     • Set and adjust the trench box from outside the excavation; nobody goes in until it is in place.
     • Cut slopes and benches to the angle the competent person set for the soil type.
     • Use only trench boxes with the manufacturer's tabulated data on site and don't exceed rated depth.
   • Pinch points and swinging loads when rigging the trench boxMedium
     • Inspect chains and shackles before lifting; use tag lines to guide the box.
     • Keep hands off the box while it moves and wear work gloves.

5. 5. Inspect and enter the excavation

   • Cave-in from water, cracks, or changed conditionsHigh
     • The competent person inspects before each shift, after rain, and after any change. Look for cracks, bulges, water, and sloughing.
     • Pump out standing water before entry; get out right away if you see the walls move.
   • Falling while climbing in or outMedium
     • In excavations 4 ft or deeper, place a ladder within 25 ft of every worker.
     • Extend the ladder 3 ft above the edge, tie it off, and face the ladder with 3 points of contact.
   • Bad air (low oxygen or fumes) in deep or low areasMedium
     • Test the air with a gas monitor before entry in excavations over 4 ft where bad air could build up, like near landfills, fuel tanks, or sewer lines.
     • Keep gas-powered pumps and compactors out of the hole or vent the exhaust away.

6. 6. Hand-finish the bottom and lay out footings

   • Struck by the bucket while working near it in the holeHigh
     • Stop the machine and lower the bucket to the ground before anyone works within its reach.
     • Use one person to give signals to the operator.
   • Back strain from shoveling and lifting formsMedium
     • Let the machine do the heavy cuts and use the bucket to lower forms and rebar.
     • Rotate shovel work and lift with your legs; get help for loads over 50 lb.
   • Heat or cold stress in the holeMedium
     • Provide cool water, shade, and rest breaks; give new workers time to get used to the heat.
     • Watch each other for dizziness, cramps, or confusion and report it right away.

7. 7. Secure the site at end of day and clean up

   • Workers or public falling into the open excavationHigh
     • Put up fence or barricades around the whole excavation before leaving.
     • Cover or barricade any wells, pits, or shafts.
     • Use guardrails or fall protection on walkways over excavations 6 ft or deeper.
   • Trips on tools, hoses, and loose debrisLow
     • Pick up tools, coil hoses, and keep walkways clear.
     • Park equipment away from the edge, bucket down, keys removed.