Lessons Learned–Serious Occurrence Report
Title: PVC Fuel Gas Line Strike
Date of Incident: 2 October 2006
Business or Performance Unit: NAGas SPU/South
Location of Incident: Garland Scott 1-44
Function: Construction/Maintenance
Type of Incident: Line strike Incident while ditching to install
electrical service to a pumping unit.
Region/Country: North America/USA
Business Stream: Upstream E&P
Lesson Origin: Serious Occurrence (SOR)
Brief Account of Incident: While excavating with a trenching
machine, an electrical construction crew working on a BP
pumping unit electrification project hit a landowner’s 2” PVC
irrigation fuel gas line. The line had an operating pressure of ~24
psig. The landowner met previously with the construction crew
supervisor and identified a water line within the work area and
several others outside the dig area, but stated: “The water line is
the only line that [he was] aware of.” BP, the contractor, the land
owner, and the rural gas supply company had located their lines
as part of a Dig-TESS response, all were outside the ground
disturbance area except the landowner’s water line which was
located and hand exposed before digging. Based upon the line
markings and the landowner’s statement the BP job sponsor and
construction crew believed there were no other lines inside the
ground disturbance zone.
Actual or Potential Outcome: There were no injuries or fire
associated with this incident. The ditching machine operator
felt the machine “bump” the line and at the same time the line
broke releasing 39mcf of gas. The operator immediately shut the
machine down and evacuated upwind to a safe location. The BP
job sponsor was notified and within 15 minutes was able to locate
and shut in the gas source.
Golden Rules: Ground Disturbance
(All underground hazards were not identified, located and if
necessary, isolated.)
What Went Wrong:
Possible Immediate Causes
 3-9 Use of Protective Methods - Other:
Method for locating unknown, non-metallic lines, not used
 5-1 Protective Systems - Inadequate guards or
protective devices:
No tracer wire or above ground marker was available to aid in
locating the PVC line.
 7-8 Work Exposure to- Mechanical Hazards:
Using a ditching machine – Although other methods/equipment
could have been used to prevent damaging a buried line (hydroFor Additional Information Contact:
Dan Lawson- Anadarko OC Manager (806) 371-4494
vac or hand digging), they are not practical for excavations over
large distances as was the case in this incident.
Possible System Causes:
 15-15 Communication - Other:
Although some lines were marked/located the line that was
struck was not known to exist.
Resultant Actions:
 BP Construction Specialist will update documentation to show
location & orientation of this 2-inch PVC fuel gas line.
 Asset Ground Disturbance Champion will determine that
current Ground Disturbance training material and instruction
adequately addresses the necessity for surveying surface
indicators such as, buildings that may use gas, meters, engines,
and that there is a potential for unknown lines near trenches
where other lines have been buried.
 Questioning of landowner to include – “Do you have any
natural gas supplied equipment, irrigation motors, heaters, etc?”
Knowing where the equipment is and where the fuel source is
located may not always identify where the lines are located but
will provide additional information to further reduce risk by
noting possible undefined/unmarked lines in the dig area and, if
appropriate, will allow the source to be shut-in before digging.
Key Message:
In this incident personnel followed the requirements of the
Ground Disturbance policy to ensure a safe excavation could be
completed; however, following a policy will not always eliminate
all risk. In many instances there can be unknown factors that
present hazards. We must, in all cases, step back and look for the
“unknowns” that may pose a risk to the safe operations on any job
site. Recognize that landowners may not know about the
existence of every line buried on their property, so ask the
question, “What equipment do you have that uses natural gas,
electricity, water, etc?” If these lines are deemed to be within the
dig area, then make sure the lines are identified and/or the source
shut-in before digging.