Incident details
Operator, cause, commodity and consequences with raw source fields.
GD incident on 2018-12-07 — MT
Operator
Northwestern Corporation
Cause
Notification Issue
Commodity
Natural Gas
Program
GD
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$45,585
Incident datetime
2018-12-07 16:26
Report number
Location
MT, SILVER BOW
Narrative
*update: after further inspection of the area where this incident occurred, it would be appropriate to correct the class location from 1 to a class 3. Also, with further review of the root cause - nwe has changed the selection to "one call notification practices not sufficient". The reason that "excavation practices not sufficient" was originally selected was due to, in addition to the one call center not being contacted, the contractor was not to be doing any work in any context at the location where the incident occurred. The work being done was completely out of the scope of the project and no work should have been being done when the line was hit. This is a reclamation projected that is being led by the state of montana. ___________________________________________________________________________________________________ *no change in report - should have been marked as "final" report in original report - event occurred on december 7, 2018 northwestern energy original report was made to the nrc on december 11, 2018. This is the date when confirmed discovery was made that the loss of natural gas exceeded 3 million cubic feet. The 48 hour update was made on december 13, 2018. Two additions were given in the 48 hour update: the amount of gas lost was incorrectly reported - correct amount was 5,853 mcf (5,853,000 cubic feet). The other update was to include the contractor involved in the incident - m.K. Weeden. The nrc report number for this update is incident report # 1232850. No injuries, deaths, or evacuations occurred with this incident. No locate ticket was submitted by the excavating party when this work was being done. 16:26 mst m.K. Weeden hit a 12-inch steel gas main located near the intersection of farrell and texas ave. With an excavator. The line was an intermediate pressure line operating at 50 psig. 16:45 mst northwestern was notified by the contractor that a nwe gas line was hit near the intersection of farrell and texas ave. Emergency response was notified and northwestern energy personnel was dispatch to evaluate the hit line from a safe distance. Additional resources were contacted to assist with the assessment of damages and traffic control. Emergency response personnel was also onsite to assist. 17:00 mst northwestern energy with other personnel created a 360 degree zone around the location of the hit line and was monitoring the gas levels to create a safe zone. Continuous air monitoring was done until the flow of gas was shut down. 17:10 mst due to the size of the line, northwestern energy needed further assistance by our gas transmission department with equipment and materials to make the repair. 17:30 mst more nwe personnel arrived on site and further evaluation was conducted to finalize the safest and best way to correct the situation. 03:45 mst the flow of gas was shut down by inserting stopper. With further investigation of the pipe once safe, it was found that the damage by the excavator bucket created two punctures holes in the pipe. One of the punctures was measured at 3 inches by 2 inches. The second measured at 4 inches by 3 inches. 8:15 mst repairs were completed on december 8th and pipe line was placed back in service.
Detailed record list
Occurred At
2018-12-07 16:26:00
Year
2018
Report Received Date
2019-01-04 00:00:00
Iyear
2018.0
Report Number
20190003.0
Supplemental Number
31515.0
Report Type
Supplemental Final
Operator Id
31632
Name
Northwestern Corporation
Operator Street Address
3010 W. 69th St.
Operator City Name
Sioux Falls
Operator State Abbreviation
SD
Operator Postal Code
57108
Local Datetime
2018-12-07 16:26:00
Location Street Address
Intersection Of Farrell And Texas Ave.
Location City Name
Butte
Location County Name
Silver Bow
Location State Abbreviation
MT
Location Postal Code
59701
Location Latitude
46.0052
Location Longitude
-112.5157
Nrc Rpt Datetime
2018-12-11 10:32:00
Nrc Rpt Num
1232639
Commodity Released Type
Natural Gas
Unintentional Release
5853.0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Ignite Ind
No
Explode Ind
No
Num Pub Evacuated
0.0
Incident Identified Datetime
2018-12-07 16:26:00
On Site Datetime
2018-12-07 16:45:00
Federal
No
Location Type
Utility Right-Of-Way / Easement
Incident Area Type
Underground
Incident Area Subtype
Exposed Due To Excavation
Depth Of Cover
63.0
Crossing
No
Pipe Facility Type
Investor Owned
System Part Involved
Main
Pipe Diameter
12.0
Pipe Specification
Schedule 40
Pipe Manufacturer
Unknown
Material Involved
Steel
Steel Seam Type
Seamless
Steel Seam Type Details
Seamless
Wt Steel
0.25
Release Type
Mechanical Puncture
Puncture Axial
3.0
Puncture Circum
2.0
Class Location Type
Class 3 Location
Est Cost Oper Paid
2400.0
Est Cost Prop Damage
45585.0
Est Cost Emergency
0.0
Est Cost Other
0.0
Est Cost Unintentional Release
38796.0
Prpty
86781.0
Commercial Affected
0.0
Industrial Affected
0.0
Residences Affected
0.0
Accident Psig
23.0
Normal Psig
50.0
Mop Psig
52.0
Accident Pressure
Pressure Did Not Exceed Maop
Scada In Place Ind
Yes
Scada Operating Ind
Yes
Scada Functional Ind
Yes
Scada Detection Ind
Yes
Scada Conf Ind
Yes
Accident Identifier
Notification From Third Party That Caused The Incident
Investigation Status
No, the operator did not find that an investigation of the controller(s) actions or control room issues was necessary due to: (provide an explanation for why the operator did not investigate)
Investigation Status Details
It was known that the controller was not involved in the incident.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Excavation Damage
Cause Details
Excavation Damage By Third Party
Ex Party Type
Excavation Damage By Third Party
Prior Notification Ind
No
Notify Cga Dirt
Yes
Public Util Easement Row Ind
Yes
Excavator Type
Contractor
Excavator Equipment
Backhoe/trackhoe
Work Performed
Site Development
One Call Notified Ind
No
Service Interruption
No
Root Cause Category
Notification Issue
Root Cause Type
No Notification Made To The One-Call Center/811
Preparer Name
D**** M*******
Preparer Title
Dot Coordinator
Preparer Email
D*************@n***********.com
Preparer Telephone
406-497-3218
Authorizer Name
D**** M*******
Authorizer Title
Dot Coordinator
Authorizer Telephone
406-497-3218
Authorizer Email
D*************@n***********.com
Narrative
*update: after further inspection of the area where this incident occurred, it would be appropriate to correct the class location from 1 to a class 3. Also, with further review of the root cause - nwe has changed the selection to "one call notification practices not sufficient". The reason that "excavation practices not sufficient" was originally selected was due to, in addition to the one call center not being contacted, the contractor was not to be doing any work in any context at the location where the incident occurred. The work being done was completely out of the scope of the project and no work should have been being done when the line was hit. This is a reclamation projected that is being led by the state of montana. ___________________________________________________________________________________________________ *no change in report - should have been marked as "final" report in original report - event occurred on december 7, 2018 northwestern energy original report was made to the nrc on december 11, 2018. This is the date when confirmed discovery was made that the loss of natural gas exceeded 3 million cubic feet. The 48 hour update was made on december 13, 2018. Two additions were given in the 48 hour update: the amount of gas lost was incorrectly reported - correct amount was 5,853 mcf (5,853,000 cubic feet). The other update was to include the contractor involved in the incident - m.K. Weeden. The nrc report number for this update is incident report # 1232850. No injuries, deaths, or evacuations occurred with this incident. No locate ticket was submitted by the excavating party when this work was being done. 16:26 mst m.K. Weeden hit a 12-inch steel gas main located near the intersection of farrell and texas ave. With an excavator. The line was an intermediate pressure line operating at 50 psig. 16:45 mst northwestern was notified by the contractor that a nwe gas line was hit near the intersection of farrell and texas ave. Emergency response was notified and northwestern energy personnel was dispatch to evaluate the hit line from a safe distance. Additional resources were contacted to assist with the assessment of damages and traffic control. Emergency response personnel was also onsite to assist. 17:00 mst northwestern energy with other personnel created a 360 degree zone around the location of the hit line and was monitoring the gas levels to create a safe zone. Continuous air monitoring was done until the flow of gas was shut down. 17:10 mst due to the size of the line, northwestern energy needed further assistance by our gas transmission department with equipment and materials to make the repair. 17:30 mst more nwe personnel arrived on site and further evaluation was conducted to finalize the safest and best way to correct the situation. 03:45 mst the flow of gas was shut down by inserting stopper. With further investigation of the pipe once safe, it was found that the damage by the excavator bucket created two punctures holes in the pipe. One of the punctures was measured at 3 inches by 2 inches. The second measured at 4 inches by 3 inches. 8:15 mst repairs were completed on december 8th and pipe line was placed back in service.
| Occurred At | 2018-12-07 16:26:00 |
|---|---|
| Year | 2018 |
| Report Received Date | 2019-01-04 00:00:00 |
| Iyear | 2018.0 |
| Report Number | 20190003.0 |
| Supplemental Number | 31515.0 |
| Report Type | Supplemental Final |
| Operator Id | 31632 PHMSA Enforcement |
| Name | Northwestern Corporation |
| Operator Street Address | 3010 W. 69th St. |
| Operator City Name | Sioux Falls |
| Operator State Abbreviation | SD |
| Operator Postal Code | 57108 |
| Local Datetime | 2018-12-07 16:26:00 |
| Location Street Address | Intersection Of Farrell And Texas Ave. |
| Location City Name | Butte |
| Location County Name | Silver Bow |
| Location State Abbreviation | MT |
| Location Postal Code | 59701 |
| Location Latitude | 46.0052 Google Maps OpenStreetMap |
| Location Longitude | -112.5157 Google Maps OpenStreetMap |
| Nrc Rpt Datetime | 2018-12-11 10:32:00 |
| Nrc Rpt Num | 1232639 NRC Report How to search |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 5853.0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Ignite Ind | No |
| Explode Ind | No |
| Num Pub Evacuated | 0.0 |
| Incident Identified Datetime | 2018-12-07 16:26:00 |
| On Site Datetime | 2018-12-07 16:45:00 |
| Federal | No |
| Location Type | Utility Right-Of-Way / Easement |
| Incident Area Type | Underground |
| Incident Area Subtype | Exposed Due To Excavation |
| Depth Of Cover | 63.0 |
| Crossing | No |
| Pipe Facility Type | Investor Owned |
| System Part Involved | Main |
| Pipe Diameter | 12.0 |
| Pipe Specification | Schedule 40 |
| Pipe Manufacturer | Unknown |
| Material Involved | Steel |
| Steel Seam Type | Seamless |
| Steel Seam Type Details | Seamless |
| Wt Steel | 0.25 |
| Release Type | Mechanical Puncture |
| Puncture Axial | 3.0 |
| Puncture Circum | 2.0 |
| Class Location Type | Class 3 Location |
| Est Cost Oper Paid | 2400.0 |
| Est Cost Prop Damage | 45585.0 |
| Est Cost Emergency | 0.0 |
| Est Cost Other | 0.0 |
| Est Cost Unintentional Release | 38796.0 |
| Prpty | 86781.0 |
| Commercial Affected | 0.0 |
| Industrial Affected | 0.0 |
| Residences Affected | 0.0 |
| Accident Psig | 23.0 |
| Normal Psig | 50.0 |
| Mop Psig | 52.0 |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Scada In Place Ind | Yes |
| Scada Operating Ind | Yes |
| Scada Functional Ind | Yes |
| Scada Detection Ind | Yes |
| Scada Conf Ind | Yes |
| Accident Identifier | Notification From Third Party That Caused The Incident |
| Investigation Status | No, the operator did not find that an investigation of the controller(s) actions or control room issues was necessary due to: (provide an explanation for why the operator did not investigate) |
| Investigation Status Details | It was known that the controller was not involved in the incident. |
| Employee Drug Test Ind | No |
| Contractor Drug Test Ind | No |
| Cause | Excavation Damage |
| Cause Details | Excavation Damage By Third Party |
| Ex Party Type | Excavation Damage By Third Party |
| Prior Notification Ind | No |
| Notify Cga Dirt | Yes |
| Public Util Easement Row Ind | Yes |
| Excavator Type | Contractor |
| Excavator Equipment | Backhoe/trackhoe |
| Work Performed | Site Development |
| One Call Notified Ind | No |
| Service Interruption | No |
| Root Cause Category | Notification Issue |
| Root Cause Type | No Notification Made To The One-Call Center/811 |
| Preparer Name | D**** M******* |
| Preparer Title | Dot Coordinator |
| Preparer Email | D*************@n***********.com |
| Preparer Telephone | 406-497-3218 |
| Authorizer Name | D**** M******* |
| Authorizer Title | Dot Coordinator |
| Authorizer Telephone | 406-497-3218 |
| Authorizer Email | D*************@n***********.com |
| Narrative | *update: after further inspection of the area where this incident occurred, it would be appropriate to correct the class location from 1 to a class 3. Also, with further review of the root cause - nwe has changed the selection to "one call notification practices not sufficient". The reason that "excavation practices not sufficient" was originally selected was due to, in addition to the one call center not being contacted, the contractor was not to be doing any work in any context at the location where the incident occurred. The work being done was completely out of the scope of the project and no work should have been being done when the line was hit. This is a reclamation projected that is being led by the state of montana. ___________________________________________________________________________________________________ *no change in report - should have been marked as "final" report in original report - event occurred on december 7, 2018 northwestern energy original report was made to the nrc on december 11, 2018. This is the date when confirmed discovery was made that the loss of natural gas exceeded 3 million cubic feet. The 48 hour update was made on december 13, 2018. Two additions were given in the 48 hour update: the amount of gas lost was incorrectly reported - correct amount was 5,853 mcf (5,853,000 cubic feet). The other update was to include the contractor involved in the incident - m.K. Weeden. The nrc report number for this update is incident report # 1232850. No injuries, deaths, or evacuations occurred with this incident. No locate ticket was submitted by the excavating party when this work was being done. 16:26 mst m.K. Weeden hit a 12-inch steel gas main located near the intersection of farrell and texas ave. With an excavator. The line was an intermediate pressure line operating at 50 psig. 16:45 mst northwestern was notified by the contractor that a nwe gas line was hit near the intersection of farrell and texas ave. Emergency response was notified and northwestern energy personnel was dispatch to evaluate the hit line from a safe distance. Additional resources were contacted to assist with the assessment of damages and traffic control. Emergency response personnel was also onsite to assist. 17:00 mst northwestern energy with other personnel created a 360 degree zone around the location of the hit line and was monitoring the gas levels to create a safe zone. Continuous air monitoring was done until the flow of gas was shut down. 17:10 mst due to the size of the line, northwestern energy needed further assistance by our gas transmission department with equipment and materials to make the repair. 17:30 mst more nwe personnel arrived on site and further evaluation was conducted to finalize the safest and best way to correct the situation. 03:45 mst the flow of gas was shut down by inserting stopper. With further investigation of the pipe once safe, it was found that the damage by the excavator bucket created two punctures holes in the pipe. One of the punctures was measured at 3 inches by 2 inches. The second measured at 4 inches by 3 inches. 8:15 mst repairs were completed on december 8th and pipe line was placed back in service. |
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