Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2020-09-24 — UT
Operator
Northwest Pipeline Llc
Cause
Corrosion Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$200,000
Incident datetime
2020-09-24 15:57
Report number
Location
UT
Narrative
In april of 2020 williams contracted with an in-line inspection vendor to complete tool runs on the williams northwest pipeline 1400 pocatello to burley segment. High-res mfl tool runs were conducted, and a preliminary report was provided to williams with anomalies on the week of 5/25/2020. Williams initiated projects to address anomalies in order of priority. This particular dig did not meet the same criteria as other's in the area - under called by the tool. As a result this pin hole was not discovered until remediation of other leaks in the same general area had been completed. Similar to other anomalies in the area excavation uncovered a pin-hole leak resulting from corrosion. Leak surveys prior to feature assessment did not show any signs of leaking. Assessments included aerial leak survey 9/22/2020, and ground survey 9/23/2020. There was no indication of foul odors or discolored vegetation prior to digging. The first indication of gas occurred after the feature was uncovered. It is estimated that the feature leaked from the first indication of gas for approximately 3 hours before the line was shut in and blown down from an operating pressure of about 600psig to 14psig. After assessing repair options williams project management determined that repairs would be best accomplished through pipe replacement. The preliminary cost of repairs exceeds $50,000, with cost of contractor and internal labor approaching $200,000. It was determined that this qualified as a DOT report-able incident based on cost when williams management settled on pipe replacement as the preferred repair option on 9/24/2020. The nrc was initially notified of the incident on 9/24/2020. The line was returned to service on 10/21/2020
Detailed record list
Report Received Date
2020-10-22 00:00:00
Iyear
2020
Report Number
20200109
Supplemental Number
34514
Report Type
Supplemental Final
Operator Id
13845
Name
Northwest Pipeline Llc
Operator Street Address
295 Chipeta Way
Operator City Name
Salt Lake City
Operator State Abbreviation
UT
Operator Postal Code
84108
Local Datetime
2020-09-24 15:57:00
Time Zone
Mountain
Daylight Savings Ind
Yes
Location Latitude
42.65311312
Location Longitude
-113.0101373
Nrc Rpt Num
1288206
Nrc Rpt Datetime
2020-09-24 17:18:00
Additional Nrc Report Numbers
1288427
Commodity Released Type
Natural Gas
Unintentional Release
123.2
Intentional Release
10555
Accompanying Liquid
0
Fatality Ind
No
Fatal
0
Injury Ind
No
Injure
0
Status When Identified
Normal Operation, Includes Pauses During Maintenance
Shutdown Due Accident Ind
Yes
Shutdown Datetime
2020-09-24 18:43:00
Restart Datetime
2020-10-21 11:15:00
Communication State Fed Ind
Yes
Party Initiated Communication
Operator
Initial Responder Com Datetime
2020-09-24 18:05:00
Ignite Ind
No
Upstream Action Taken
Valve Closure
Upstream Valve Close Datetime
2020-09-24 18:43:00
Downstream Action Taken
Valve Closure
Downstream Vlv Close Datetime
2020-09-24 18:25:00
Num Pub Evacuated
0
Incident Identified Datetime
2020-09-24 15:57:00
On Site Datetime
2020-09-24 15:57:00
On Off Shore
Onshore
Onshore State Abbreviation
Id
Onshore Postal Code
83211
Onshore City Name
Not Within A Municipality
Onshore County Name
Power
Designated Location
Milepost
Designated Name
626.9
Pipe Fac Name
Williams Northwest Pipeline
Segment Name
Mainline 1400
Federal
No
Location Type
Pipeline Right-Of-Way
Incident Area Type
Underground
Incident Area Subtype
Under Soil
Depth Of Cover
42
Other Underground Facilities
No
Crossing
No
Pipe Facility Type
Interstate
System Part Involved
Onshore Pipeline, Including Valve Sites
Item Involved
Pipe
Pipe Type
Pipe Body
Pipe Diameter
22
Puddle Weld Ind
No
Pipe Wall Thickness
0.25
Pipe Smys
52000
Pipe Specification
Api 5lx
Pipe Seam Type
Dsaw
Pipe Manufacturer
Consolidated Western
Pipe Coating Type
Asphalt
Coating Applied Ind
Unknown
Installation Year
1955
Manufactured Year
1955
Material Involved
Carbon Steel
Release Type
Leak
Leak Type
Pinhole
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
443
Heat Damage Ind
No
Non Heat Damage Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
149
Est Cost Intentional Release
12772
Est Cost Prop Damage
200000
Est Cost Emergency
0
Est Cost Other
0
Gas Cost In Mcf
1.21
Prpty
212921
Num Persons Hosp Not Ovnght
0
Num Injured Treated By Emt
0
Num Resident Building Affctd
0
Num Business Building Affctd
0
Wildlife Impact Ind
No
Accident Psig
591
Gas Flow In Pipe In Mcf
178500
Mop Psig
850
Mop Cfr Section
192.619(A)(3)
Maop Established Date
1970-11-12 00:00:00
Maop Reversal Flow Ind
Bi-Directional
Accident Pressure
Pressure Did Not Exceed Maop
Pressure Restriction Ind
No
Gas Required Odorized Ind
No
Upstream Valve Type Ind
Manual
Downstream Valve Type Ind
Manual
Length Segment Isolated
91783
Internal Inspection Ind
Yes
Operation Complications Ind
No
Pipeline Function
Transmission System
Scada In Place Ind
Yes
Scada Operating Ind
Yes
Scada Functional Ind
Yes
Scada Detection Ind
No
Scada Conf Ind
No
Accident Identifier
Local Operating Personnel, Including Contractors
Operator Type
Operator Employee
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
Pin hole leaks were of a minor nature in terms of gas loss, and scada is not well suited for identifying these types of leaks. Leaks were discovered during follow up activities associated with in-line inspection of the line.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Corrosion Failure
Cause Details
External Corrosion
Internal External
External Corrosion
Visual Exam Results
General Corrosion
Galvanic Corrosion Ind
Yes
Field Exam Basis Ind
Yes
Underground Location
Yes
Under Cathodic Protection Ind
Yes
Cathodic Pro Start Year
1975
Shielding Evident
Yes
Cathodic Survey Type
Yes
Cp Annual Survey Ind
Yes
Cp Annual Survey Year
2019
Prior Damage
No
Collected Data Ind
Yes
Axial Magnetic Flx Lkg Ind
Yes
Axial Recent Year
2020
Axial Rcnt Propul Method
Free Swimming
Axial Rcnt Attuned Detect
Metal Loss
Axial Rcnt Atnd Dtct Metal
High Resolution
Axial Previous Year
2012
Axial Prev Propul Method
Free Swimming
Axial Prev Attuned Detect
Metal Loss
Axial Prev Atnd Dtct Metal
High Resolution
Has Hydrtst Conduc Before Ind
No
Direct Asmnt Conducted
Yes, And An Investigative Dig Was Cunducted At The Point Of The Accident
Direct Asmnt At Pnt Accdnt Yr
2020
Asmnt Confirmatory Rcnt Year
2020
Asmnt Confirmatory Rcnt Ind
Yes
Non Destructive Exam Ind
No
Preparer Name
B*** B*******
Preparer Title
Engineer Iii - Pipeline Safety
Preparer Email
B************@w*******.com
Preparer Telephone
801-584-6892
Local Contact Name
D*** D********
Local Contact Email
D****************@w*******.com
Local Contact Telephone
208-884-4300
Authorizer Name
T**** G****
Authorizer Title
Manager Pipeline Safety
Authorizer Telephone
713-215-2535
Authorizer Email
T**********@w*******.com
Narrative
In april of 2020 williams contracted with an in-line inspection vendor to complete tool runs on the williams northwest pipeline 1400 pocatello to burley segment. High-res mfl tool runs were conducted, and a preliminary report was provided to williams with anomalies on the week of 5/25/2020. Williams initiated projects to address anomalies in order of priority. This particular dig did not meet the same criteria as other's in the area - under called by the tool. As a result this pin hole was not discovered until remediation of other leaks in the same general area had been completed. Similar to other anomalies in the area excavation uncovered a pin-hole leak resulting from corrosion. Leak surveys prior to feature assessment did not show any signs of leaking. Assessments included aerial leak survey 9/22/2020, and ground survey 9/23/2020. There was no indication of foul odors or discolored vegetation prior to digging. The first indication of gas occurred after the feature was uncovered. It is estimated that the feature leaked from the first indication of gas for approximately 3 hours before the line was shut in and blown down from an operating pressure of about 600psig to 14psig. After assessing repair options williams project management determined that repairs would be best accomplished through pipe replacement. The preliminary cost of repairs exceeds $50,000, with cost of contractor and internal labor approaching $200,000. It was determined that this qualified as a DOT report-able incident based on cost when williams management settled on pipe replacement as the preferred repair option on 9/24/2020. The nrc was initially notified of the incident on 9/24/2020. The line was returned to service on 10/21/2020
| Report Received Date | 2020-10-22 00:00:00 |
|---|---|
| Iyear | 2020 |
| Report Number | 20200109 |
| Supplemental Number | 34514 |
| Report Type | Supplemental Final |
| Operator Id | 13845 PHMSA Enforcement |
| Name | Northwest Pipeline Llc |
| Operator Street Address | 295 Chipeta Way |
| Operator City Name | Salt Lake City |
| Operator State Abbreviation | UT |
| Operator Postal Code | 84108 |
| Local Datetime | 2020-09-24 15:57:00 |
| Time Zone | Mountain |
| Daylight Savings Ind | Yes |
| Location Latitude | 42.65311312 Google Maps OpenStreetMap |
| Location Longitude | -113.0101373 Google Maps OpenStreetMap |
| Nrc Rpt Num | 1288206 NRC Report How to search |
| Nrc Rpt Datetime | 2020-09-24 17:18:00 |
| Additional Nrc Report Numbers | 1288427 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 123.2 |
| Intentional Release | 10555 |
| Accompanying Liquid | 0 |
| Fatality Ind | No |
| Fatal | 0 |
| Injury Ind | No |
| Injure | 0 |
| Status When Identified | Normal Operation, Includes Pauses During Maintenance |
| Shutdown Due Accident Ind | Yes |
| Shutdown Datetime | 2020-09-24 18:43:00 |
| Restart Datetime | 2020-10-21 11:15:00 |
| Communication State Fed Ind | Yes |
| Party Initiated Communication | Operator |
| Initial Responder Com Datetime | 2020-09-24 18:05:00 |
| Ignite Ind | No |
| Upstream Action Taken | Valve Closure |
| Upstream Valve Close Datetime | 2020-09-24 18:43:00 |
| Downstream Action Taken | Valve Closure |
| Downstream Vlv Close Datetime | 2020-09-24 18:25:00 |
| Num Pub Evacuated | 0 |
| Incident Identified Datetime | 2020-09-24 15:57:00 |
| On Site Datetime | 2020-09-24 15:57:00 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Id |
| Onshore Postal Code | 83211 |
| Onshore City Name | Not Within A Municipality |
| Onshore County Name | Power |
| Designated Location | Milepost |
| Designated Name | 626.9 |
| Pipe Fac Name | Williams Northwest Pipeline |
| Segment Name | Mainline 1400 |
| Federal | No |
| Location Type | Pipeline Right-Of-Way |
| Incident Area Type | Underground |
| Incident Area Subtype | Under Soil |
| Depth Of Cover | 42 |
| Other Underground Facilities | No |
| Crossing | No |
| Pipe Facility Type | Interstate |
| System Part Involved | Onshore Pipeline, Including Valve Sites |
| Item Involved | Pipe |
| Pipe Type | Pipe Body |
| Pipe Diameter | 22 |
| Puddle Weld Ind | No |
| Pipe Wall Thickness | 0.25 |
| Pipe Smys | 52000 |
| Pipe Specification | Api 5lx |
| Pipe Seam Type | Dsaw |
| Pipe Manufacturer | Consolidated Western |
| Pipe Coating Type | Asphalt |
| Coating Applied Ind | Unknown |
| Installation Year | 1955 |
| Manufactured Year | 1955 |
| Material Involved | Carbon Steel |
| Release Type | Leak |
| Leak Type | Pinhole |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 443 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 149 |
| Est Cost Intentional Release | 12772 |
| Est Cost Prop Damage | 200000 |
| Est Cost Emergency | 0 |
| Est Cost Other | 0 |
| Gas Cost In Mcf | 1.21 |
| Prpty | 212921 |
| Num Persons Hosp Not Ovnght | 0 |
| Num Injured Treated By Emt | 0 |
| Num Resident Building Affctd | 0 |
| Num Business Building Affctd | 0 |
| Wildlife Impact Ind | No |
| Accident Psig | 591 |
| Gas Flow In Pipe In Mcf | 178500 |
| Mop Psig | 850 |
| Mop Cfr Section | 192.619(A)(3) View CFR 49 §192 |
| Maop Established Date | 1970-11-12 00:00:00 |
| Maop Reversal Flow Ind | Bi-Directional |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Pressure Restriction Ind | No |
| Gas Required Odorized Ind | No |
| Upstream Valve Type Ind | Manual |
| Downstream Valve Type Ind | Manual |
| Length Segment Isolated | 91783 |
| Internal Inspection Ind | Yes |
| Operation Complications Ind | No |
| Pipeline Function | Transmission System |
| Scada In Place Ind | Yes |
| Scada Operating Ind | Yes |
| Scada Functional Ind | Yes |
| Scada Detection Ind | No |
| Scada Conf Ind | No |
| Accident Identifier | Local Operating Personnel, Including Contractors |
| Operator Type | Operator Employee |
| 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 | Pin hole leaks were of a minor nature in terms of gas loss, and scada is not well suited for identifying these types of leaks. Leaks were discovered during follow up activities associated with in-line inspection of the line. |
| Employee Drug Test Ind | No |
| Contractor Drug Test Ind | No |
| Cause | Corrosion Failure |
| Cause Details | External Corrosion |
| Internal External | External Corrosion |
| Visual Exam Results | General Corrosion |
| Galvanic Corrosion Ind | Yes |
| Field Exam Basis Ind | Yes |
| Underground Location | Yes |
| Under Cathodic Protection Ind | Yes |
| Cathodic Pro Start Year | 1975 |
| Shielding Evident | Yes |
| Cathodic Survey Type | Yes |
| Cp Annual Survey Ind | Yes |
| Cp Annual Survey Year | 2019 |
| Prior Damage | No |
| Collected Data Ind | Yes |
| Axial Magnetic Flx Lkg Ind | Yes |
| Axial Recent Year | 2020 |
| Axial Rcnt Propul Method | Free Swimming |
| Axial Rcnt Attuned Detect | Metal Loss |
| Axial Rcnt Atnd Dtct Metal | High Resolution |
| Axial Previous Year | 2012 |
| Axial Prev Propul Method | Free Swimming |
| Axial Prev Attuned Detect | Metal Loss |
| Axial Prev Atnd Dtct Metal | High Resolution |
| Has Hydrtst Conduc Before Ind | No |
| Direct Asmnt Conducted | Yes, And An Investigative Dig Was Cunducted At The Point Of The Accident |
| Direct Asmnt At Pnt Accdnt Yr | 2020 |
| Asmnt Confirmatory Rcnt Year | 2020 |
| Asmnt Confirmatory Rcnt Ind | Yes |
| Non Destructive Exam Ind | No |
| Preparer Name | B*** B******* |
| Preparer Title | Engineer Iii - Pipeline Safety |
| Preparer Email | B************@w*******.com |
| Preparer Telephone | 801-584-6892 |
| Local Contact Name | D*** D******** |
| Local Contact Email | D****************@w*******.com |
| Local Contact Telephone | 208-884-4300 |
| Authorizer Name | T**** G**** |
| Authorizer Title | Manager Pipeline Safety |
| Authorizer Telephone | 713-215-2535 |
| Authorizer Email | T**********@w*******.com |
| Narrative | In april of 2020 williams contracted with an in-line inspection vendor to complete tool runs on the williams northwest pipeline 1400 pocatello to burley segment. High-res mfl tool runs were conducted, and a preliminary report was provided to williams with anomalies on the week of 5/25/2020. Williams initiated projects to address anomalies in order of priority. This particular dig did not meet the same criteria as other's in the area - under called by the tool. As a result this pin hole was not discovered until remediation of other leaks in the same general area had been completed. Similar to other anomalies in the area excavation uncovered a pin-hole leak resulting from corrosion. Leak surveys prior to feature assessment did not show any signs of leaking. Assessments included aerial leak survey 9/22/2020, and ground survey 9/23/2020. There was no indication of foul odors or discolored vegetation prior to digging. The first indication of gas occurred after the feature was uncovered. It is estimated that the feature leaked from the first indication of gas for approximately 3 hours before the line was shut in and blown down from an operating pressure of about 600psig to 14psig. After assessing repair options williams project management determined that repairs would be best accomplished through pipe replacement. The preliminary cost of repairs exceeds $50,000, with cost of contractor and internal labor approaching $200,000. It was determined that this qualified as a DOT report-able incident based on cost when williams management settled on pipe replacement as the preferred repair option on 9/24/2020. The nrc was initially notified of the incident on 9/24/2020. The line was returned to service on 10/21/2020 |
External Resources
PHMSA pipeline safety insights.
Product
Features
Company
All rights reserved. Copyright © by ClearPHMSA