IBEW Underground Tunnel Safety
Core Safety Principles for Operating Underground
A detailed Job Hazard Analysis (JHA) should be performed at the start of every work day.
Never enter an unsafe space.
Never bypass a safety system for any reason, under any circumstances.
Never ignore air monitoring readings.
Never let schedule pressure rush you past a safety step.
Always look out for your fellow worker.
Never hesitate to report an incident or ask a question. Contact IBEW 11 Safety — that's what they're there for.
essential Personal protective equipment (PPE) for tunnel work
Underground hazards & controls
Collapse & Ground stability
Tunnel collapses and cave-ins remain one of the most serious risks. Recognize the signs before movement happens.
Early warning signs:
Cracking or popping sounds
Falling dust or small debris
Bulging walls or shifting supports
Water seepage increasing suddenly
Hazards:
Loose or fractured rock
Water intrusion
Vibration from blasting or equipment
Improper or failed ground support
OSHA requires:
Inspection of tunnel walls, face, and roof every shift
Scaling or supporting loose material
Competent person oversight at all times
Air Quality & Atmospheric Hazards
A respiratory injury can end your career and affect you the rest of your life. Know the signs.
Early warning signs:
Headache, dizziness, confusion
Burning eyes or throat
Sudden fatigue or nausea
Workers “not acting right”
Atmospheric Risks:
Oxygen levels below 19.5%
Exposure to toxic gases such as Carbon monoxide (CO), Hydrogen sulfide (H₂S), and Nitrogen dioxide (NO₂)
Diesel exhaust exposure from heavy machinery
Silica dust (drilling, cutting)
Required Controls:
Atmospheric test on entry and at intervals
Regular ventilation system checks
Confined Space Entry Permit required
Electrical hazards unique to tunnel work
Electricians face compounded risk underground. These environments can amplify electrical hazards due to wet conditions, tight quarters, and reduced escape time.
Risk of Injury:
Elevated risk of electrocution
Underground Tunnel Hazards:
Energized cables in confined spaces
Moisture increasing conductivity
Limited clearance around live systems
Poor lighting conditions
Required Practices:
Lockout/Tagout (LOTO)
Proper grounding and bonding
Arc flash protection
Insulated tools and PPE
Heavy Equipment & Struck-By Hazards
Heavy equipment doesn’t stop fast—and tunnels don’t leave room. These hazards are only intensified by the confined space you are working in and limited visibility.
Risk of Injury:
Struck-by incidents
Caught-between hazards
Crushing injuries
Equipment Hazards:
Haul trucks and loaders
Tunnel boring machinery
Hoisting systems
Moving materials in tight shafts
Key Safety Protocols:
Never position yourself between equipment and a fixed object
Stay out of the swing radius of all equipment
Establish eye contact with operators before entering their zone
Use a spotter when equipment is moving in confined areas
Never walk under a suspended load
Access, Egress & Emergency
Underground work limits escape routes and visibility. You should always be thinking of an escape route. If you don’t know your way out, you are already behind.
Atmospheric Risks:
Fire or explosion
Flooding
Equipment failure
Gas release
Required Controls:
Clearly marked escape routes
Secondary egress where possible
Check-in/check-out system for accountability
Emergency communication systems
OSHA mandates tracking all workers underground and maintaining evacuation procedures .
Human Factors & fatigue
Real conditions underground have a serious effect on your health. It is physically demanding. You must stay aware of your surroundings and remain hydrated.
Potential issues include:
No natural light
Loss of time awareness
High physical demand
Heat and humidity
Key Practices:
Maintain situational awareness
Stay hydrated
Work at a steady, sustainable pace
Speak up when something isn’t right