Job Hazard Analysis · Excavation & Sitework

Job Hazard Analysis: Trenching for utilities

Digging, protecting, and backfilling trenches for water, sewer, electrical, or gas lines using a mini or full-size excavator. Covers trenches up to 20 ft deep in soil. Includes utility locates, spoil placement, trench boxes or sloping, pipe laying, and backfill. Weather, nearby traffic, and soil type change daily and must be checked by the competent person before each shift.

Published 2026-10-23

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

Step	Hazard	Risk	Controls
1. Call 811, mark utilities, and set up the work zone	Striking a buried gas, electric, or fiber line	High	Call 811 and wait for all utilities to mark before any digging. Keep the ticket number on site. Walk the route with the operator and compare paint and flags to the plans. Look for meters, risers, and pedestals. Hand dig or vacuum excavate to expose lines inside the tolerance zone before using the excavator.
1. Call 811, mark utilities, and set up the work zone	Being struck by passing traffic	High	Set cones, barricades, and signs before work starts. Close the lane when the trench is near the road. Use a trained flagger with a STOP/SLOW paddle when traffic must be controlled. Wear a Class 2 or 3 high-visibility vest at all times near traffic.
2. Inspect the site and soil with the competent person	Wrong soil type or protective system leading to cave-in	High	The competent person classifies the soil (Type A, B, or C) with a visual and manual test and picks the protective system before digging. If in doubt, treat the soil as Type C. Inspect the trench at the start of each shift, after rain, and after any change. Write it down.
2. Inspect the site and soil with the competent person	Water in the trench or soil softened by rain	Medium	Pump out water with a trash pump watched by the competent person. Nobody enters standing water until it is controlled. Divert surface water away from the trench edge with berms or ditches.
3. Dig the trench with the excavator	Workers struck or crushed by the bucket or swinging counterweight	High	Barricade or flag off the full swing radius. No one walks inside it while the machine runs. Make eye contact with the operator and get a signal before approaching. The operator stops and grounds the bucket first. Never stand under a raised bucket or a suspended load.
	Machine tipping at the trench edge or on a slope	Medium	Keep tracks back from the edge and set the machine on firm, level ground. Operator wears the seat belt at all times.
	Engine noise	Low	Keep the cab door shut when possible and stay back from the running machine. Wear earplugs or earmuffs when you must shout to be heard at 3 ft.
4. Install the trench box, shoring, or slope the walls	Cave-in burying a worker in a trench 5 ft or deeper	High	Nobody enters a trench 5 ft or deeper until the box, shoring, or sloping is in place and checked by the competent person. Use the trench box only within its tabulated data. Keep the manufacturer's data sheet on site. Trenches over 20 ft need a design by a registered engineer. Set and move the box from outside the trench. Never work outside the box or between the box and the wall. Keep the box no more than 2 ft above the trench bottom.
4. Install the trench box, shoring, or slope the walls	Spoil, pipe, or tools falling into the trench	High	Keep spoil piles and materials at least 2 ft back from the edge. Keep the box walls extended above grade or use toe boards where loose material can roll in. Wear a hard hat in and around the trench.
5. Enter the trench and lay pipe or conduit	No safe way in or out of the trench	Medium	Place a ladder inside the protected area within 25 ft of every worker in trenches 4 ft or deeper. Extend the ladder 3 ft above the top and tie it off.
	Bad air or low oxygen near sewers, landfills, or gas lines	Medium	Test the air with a 4-gas meter before entry in trenches over 4 ft where bad air is possible. Keep running equipment exhaust away from the trench. Get out if the alarm sounds.
	Pinched hands or back strain handling pipe	Medium	Lower pipe with the excavator and a rated sling. Use tag lines and keep hands off pinch points. Wear cut-resistant work gloves and get help with heavy fittings.
6. Cut pipe or concrete as needed	Silica dust from cutting concrete, asphalt, or ductile pipe lining with a cut-off saw	Medium	Use a cut-off saw with a water feed running the whole cut. Cut outside the trench and stand upwind. Wear a respirator when required by the silica control plan.
6. Cut pipe or concrete as needed	Kickback and flying debris from the saw	Medium	Keep the blade guard in place and use both hands. Wear safety glasses and a face shield while cutting.
7. Backfill, compact, and clean up	Pulling the trench box or shoring while workers are still inside	High	Everyone is out of the trench before the box moves or shoring comes out. The foreman does a headcount. Remove shoring from the bottom up as backfill goes in.
	Vibration, noise, and carbon monoxide from the jumping jack or plate compactor	Medium	Do not run gas compactors inside a deep trench without air testing and ventilation. Rotate operators and wear hearing protection.
	Falling into an open trench left overnight	Medium	Cover or barricade open trenches at the end of the day with fencing, plates, or barricades. Pick up tools, pipe scraps, and trash. Store materials away from the edge.

Required PPE

Hard hat — ANSI Z89.1 hard hat at all times in and near the trench and machines.
High-visibility vest — Class 2 or 3 at all times on site and near traffic.
Safety glasses — ANSI Z87.1 at all times. Add a face shield when using the cut-off saw.
Steel- or composite-toe boots — Waterproof work boots with safety toes. Rubber boots when standing in water or mud.
Work gloves — Cut-resistant gloves when handling pipe, rebar, or trench box parts.
Hearing protection — Earplugs or earmuffs near running equipment, compactors, and saws.
Respirator — N95 or half-face with P100 filters when the silica plan requires it. Fit test and medical clearance first.

Training

Competent person for excavations named on site, trained in soil classification and protective systems
Trench hazard awareness training for all crew: cave-ins, safe entry, and spoil placement
Excavator and compactor operators trained and evaluated on the specific machine
Flagger training for anyone controlling traffic
Silica and respirator training, including fit test, for workers cutting concrete or asphalt
Gas meter use and alarm response for workers in trenches with possible bad air

Emergency

If a cave-in happens: stop all equipment and call 911 right away. Give the site address and say it is a trench collapse. Do NOT jump in to dig. A second collapse is likely. Keep everyone and machines back from the edge. Account for every worker. Only trained rescuers enter. Give first aid once the victim is out.

Official sources

29 CFR 1926.651 — Excavations — specific requirements
29 CFR 1926.652 — Requirements for protective systems
29 CFR 1926.21 — Safety training and education
29 CFR 1926.600 — Motor vehicles and mechanized equipment — equipment
29 CFR 1926.201 — Signaling (flaggers)
29 CFR 1926.1153 — Respirable crystalline silica
29 CFR 1926.100 — Head protection
29 CFR 1926.50 — Medical services and first aid

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General information, not legal advice. Templates and examples should be reviewed by a competent person before use. HardHat Binder is not affiliated with or endorsed by OSHA.