Installing or repairing underground utilities can be dangerous work.
In November 2025, a trench collapse in Yarmouth, Massachusetts, killed one employee of Revoli Construction Co. Inc. and injured another during sewer work.
In December 2025, a contractor was injured after a utility strike led to a series of three explosions at a road construction site in Quincy, Massachusetts. The incident occurred during sewer and water work, with a suspected underground electrical line strike causing the accident.
In August 2025, in Mobile, Alabama, two employees of Construction Labor Services Inc. died while working inside a manhole. They were exposed to toxic sewage gas while installing a sewer bypass.
In December 2023, a National Grid worker and a police officer were killed, and two others were injured, after a pickup truck struck their worksite on a major Massachusetts thoroughfare.
In June 2025, a construction worker was giving hand signals to an excavator operator while working in a trench box when a 3,000-pound bucket fell, crushing the lower half of the worker’s body.
Trench collapses, utility strikes, confined-space risks, struck-by incidents and traffic exposure in work zones represent the top safety hazards in underground utility work. Here’s how those accidents might have been prevented.
1. Trench and Excavation Collapse
Why it matters:
While trench fatalities have declined — from 39 in 2022 to 13 in 2024 and 12 through July 2025 — each incident is devastating. Collapses, like the one in Yarmouth, typically result from failure to bench, slope, shore or use trench boxes.
Mitigation strategies:
Always use protective systems (sloping, shielding or shoring) as required by law. OSHA requires protective systems for trenches 5 feet deep or greater to prevent cave-ins.
Ensure there is a safe way to enter and exit the trench.
Look for standing water or atmospheric hazards. Never enter a trench unless it has been properly inspected.
Refer to OSHA’s trench safety overview for quick guidance. For more detailed information, consult the OSHA Technical Manual (OTM), Section V, Chapter 2.
2. Striking Existing Underground Utilities
Why it matters:
Striking buried utilities can cause electrocution, asphyxiation, gas fires or explosions. Even severing fiber-optic, telecom or water lines carries significant liability risk if due diligence is not followed.
In 2024, there were 196,977 reports of damage to buried power, water, fiber, natural gas and other utility lines in the U.S. and Canada. Utility work accounts for a large share of these incidents, with water/sewer and telecom/cable work consistently ranking among the top contributors.
Mitigation strategies:
Call 811 to locate publicly owned underground utilities, including electric, gas, water, sewer and telecommunications lines at least 2-3 business days before planned digging.
Then engage private utility locators and ground penetrating radar providers to identify laterals, private lines, abandoned infrastructure and internal site utilities not covered by 811.
Use additional methods to improve accuracy. The American Society of Civil Engineers’ standard guideline (ASCE 38-22) defines four data quality levels for subsurface utilities:
- QL-D: Record-based information is least reliable. (from historical records, construction plans or utility records
- QL-C: Data is based on correlation with visible aboveground features such as manholes, valve boxes and hydrants
- QL-B: Data is based on surface geophysical locating methods using electromagnetic locating devices, ground penetrating radar (GPR) and other non-destructive surface methods.
- QL-A: Data offers the highest level of accuracy based on direct exposure using vacuum or pneumatic excavation.
Conduct a joint site walk with the locator to review markings, verify tolerance zones (the safety margin surrounding marked utilities and resolve discrepancies before excavation begins. Preserve all flags, stakes and paint markings.
Because markings are approximate, verify locations using hand tools or soft-dig methods within the tolerance zone.
Apply lockout/tagout procedures and de-energize lines when possible, confirming they are de-energized before work begins.
Develop and communicate emergency response plans for utility strikes. Competent persons should be able to recall these procedures immediately.
3. Struck-By Incidents
Why it matters:
Utility workers face serious risk from falling, flying, swinging or rolling objects, including vehicles, equipment and loads. According to OSHA, approximately 75% of struck-by fatalities involve heavy equipment such as trucks or cranes.
In the case of the worker struck by a bucket incident referenced above, the employer was cited for failing to use a quick-coupler safety latch on the excavator that could have prevented the accident.
Mitigation strategies:
Inspect equipment before operation. Ensure quick couplers are properly engaged using approved safety checks, visual indicators and warning devices. Engage the safety locking pin before lifting attachments.
Use trained signalers and qualified operators. Never assume the operator can see you.
Require consistent use of high-visibility personal protective equipment.
Establish positive controls such as barriers and berms to block or deflect errant vehicles.
When purchasing equipment, prioritize machines with advanced awareness technologies, such as panoramic cameras and human-recognition detection systems.
4. Hazardous Atmospheres and Confined Spaces
Why it matters:
Utility workers frequently encounter confined spaces — such as manholes, trenches and vaults — that may contain life-threatening atmospheres, including low oxygen (less than 19.5%) and toxic gases.
Methane, hydrogen sulfide, carbon monoxide and oxygen deficiency can quickly overwhelm workers. An average of about 100 workers die in confined spaces each year in the United States, often including would-be rescuers.
In the Alabama incident cited above, federal investigators found the employer lacked confined-space entry programs, training and emergency response plans.
Mitigation strategies:
Ensure workers understand confined-space hazards and required precautions. OSHA requires training for all entrants.
Treat spaces as permit-required when applicable under OSHA 1926.1204.
Perform pre-entry atmospheric testing with calibrated instruments and continuously monitor conditions.
Use forced-air ventilation when needed.
Assign trained attendants and ensure rescue plans and equipment are in place.
5. Traffic Exposure and Public Interaction in Work Zones
Why it matters:
Underground work often occurs in active roadways. Workers face risks from live traffic, distracted drivers and debris.
In 2023, there were 899 work zone fatalities — more than two per day — and 39,000 injuries.
Mitigation strategies:
Implement a traffic control plan that follows the Manual on Uniform Traffic Control Devices (MUTCD).
Use warning signs, channelizing devices, barricades, flaggers, attenuators and positive barriers such as Jersey barriers.
Schedule high-risk work during low-traffic periods and coordinate with local authorities.
Provide certified flagger training and require high-visibility PPE at all times.
Refer to OSHA regulations on signaling and personal protective equipment for additional guidance.
Make a Commitment to Safety
Every underground utility jobsite presents a mix of visible and hidden risks — from moving vehicles to unseen hazards belowground. However, most incidents are preventable.
By following OSHA and MUTCD standards and preparing crews with proper training and emergency plans, contractors can significantly reduce risk and protect their teams. Safety is not a one-time action — it is a daily commitment.
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