Field Lesson: The HDD Crossing That Wasn't Daylighted
- undergroundtruth
- Aug 16
- 2 min read
Updated: 3 hours ago
On November 16, 2016, a directional-drilling crew installing underground fiber conduit in Canton, Illinois damaged an Ameren natural-gas line. The release later contributed to an explosion at a commercial building. One Ameren employee was killed and 11 people were injured.
This is not a made-up cautionary tale. The National Transportation Safety Board investigated the event and concluded that third-party damage from the directional drilling caused the gas release. The NTSB also identified a critical field decision: the contractor did not excavate at the utility crossing to visually verify the crossing while the bore was in progress and until the drill was clear of the underground facilities.
The field lesson
A paint mark on the ground is information. A daylighted utility is confirmation. Those are not the same thing.
When an HDD path crosses a critical gas, electric, water, sewer, or communications facility, the crew needs a plan that makes the crossing visible and verifiable. Potholing or vacuum excavation gives the operator, locator, and foreman an actual reference point for depth, horizontal position, separation, and drill-head progress.
The lesson is bigger than simply saying “call 811.” One-call tickets and marks start the process, but the highest-risk crossings still demand field verification. The operator should know where the utility is, the locator should know where the head is, and the crew should have a clear stop point if the numbers stop making sense.
What crews can carry forward
Daylight critical crossings before the drill reaches them.
Do not treat tolerance-zone paint as exact depth information.
Establish a stop-work trigger for unexpected resistance, lost signal, conflicting depths, or questionable marks.
Keep the bore profile and pothole information where the operator and locator can use it in real time.
If a gas line is damaged or suspected of being damaged, get people away from the hazard and initiate emergency response immediately.
Production matters. Footage matters. But no footage is worth drilling blind through a crossing that could have been exposed and verified.
UGT takeaway: If you cannot prove the crossing is clear, the bore is not ready to pass it.
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