| An underground utility line that has been inadvertently installed through a sewer pipe is known as a “cross bore.” A cross bore can go unnoticed until the utility line blocks the flow of waste in a sewer lateral. Removing the sewer blockage with mechanical clearing equipment can damage the cross bore, resulting in personal injury and property damage. |
| To order our FREE safety training booklets, visit the Duke Energy first responder safety website. |
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| The Risks of Cross-Bore Damage |
| If clearing equipment cuts into a cross‑bored natural gas pipe, leaking gas can enter the sewer system, posing a fire and explosion risk in multiple structures. Electrical cross bores pose risks as well: A plumber or drain cleaner who contacts a cross‑bored electric line with clearing equipment may suffer a serious electrical shock. |
| Dispatch Response |
| Upon receiving the report of a confirmed or suspected cross‑bore incident, initiate a full public safety response appropriate to the reported hazard. If a natural gas cross bore is involved, instruct the caller to avoid using anything that could create a spark and to evacuate the premises immediately. Once first responders have been toned, notify Duke Energy of any reported cross‑bore incident and specify the involved utility system (electric or gas). |
| Firefighter Response for a Damaged Natural Gas Cross Bore |
| 1. |
Approach cautiously. Park at least 100 feet from the front of the building, upwind and away from manhole covers and storm sewer grates. |
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| 2. |
Request the response of sewer department personnel and a map of the sewer system, as gas may rapidly migrate through sewer pipes and accumulate in multiple structures. |
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| 3. |
Do NOT open or close underground gas valves in the street at any time. |
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| 4. |
Evacuate per the DOT Emergency Response Guide 115. |
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| 5. |
If you have been trained to do so, use a properly calibrated combustible gas indicator (CGI) around nearby manholes, vaults and sewer drains. |
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| 6. |
Do NOT pull manhole covers to vent gas from sewer systems. Work with Duke Energy to develop a plan for venting manholes. |
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| 7. |
Never ventilate a building without first coordinating with Duke Energy and verifying gas has been shut off and ignition sources have been eliminated. |
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| 8. |
Do NOT enter structures unless operations are coordinated with Duke Energy and approved by your incident commander. |
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| 9. |
If you are assigned to enter a structure, do so only with full personal protective equipment (PPE) including self‑contained breathing apparatus (SCBA). |
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| 10. |
If power ventilation is necessary, use intrinsically safe ventilators and positive pressure ventilation on the upwind side. Remember, if a high concentration of gas is present, it may fall into the explosive range as a structure is ventilated. |
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| 11. |
Have a charged hand line with a fog nozzle ready to cool combustible exposures and assist with rescue operations in the event of a fire. |
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| Would You Like to Know More? |
| Additional utility safety tips, case studies, instructional videos and training tools can all be found, at no charge to you, on Duke Energy's first responder safety website. |
