Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2025-04-04 — NE
Operator
Northern Natural Gas Co
Cause
Natural Force Damage
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$170,000
Incident datetime
2025-04-04 00:00 UTC
Report number
Location
NE
Narrative
On march 11, 2025, at 1335 hours, a technician arrived on-site at the blooming prairie, mn branch line regulator station (mnr-0103) for regular maintenance and found bubbles coming up from below ground near pipeline facilities. A plan was developed to reduce pressure for investigation and evaluation of the cause of the leak. Third-party contractors were mobilized to preform excavation and repairs. After excavation, it was determined that a 1/4-inch nipple on the cbc01 valve body bleed riser had cracked and was leaking. On march 13, 2025, at 1240 hours, repairs were completed with new components and tested for leaks. Leak checks were performed at 100psig intervals as pressure was restored with no leaks identified. Field operations completed returning the mnb73202 pipeline back to regular operating configuration and pressure on march 13, 2025, at 1813 hours. Investigation concluded the body bleed riser was not sufficiently supported and due to years of ground freeze and thaws, the nipple body cracked causing the event. The replacement body bleed riser was installed with a rigid connection to prevent reoccurrence.
Detailed record list
Report Received Date
2025-04-04 00:00:00
Iyear
2025
Report Number
20250033
Supplemental Number
40785
Report Type
Supplemental Final
Operator Id
13750
Name
Northern Natural Gas Co
Operator Street Address
1111 South 103rd Street
Operator City Name
Omaha
Operator State Abbreviation
NE
Operator Postal Code
68124
Time Zone
Central
Daylight Savings Ind
Yes
Location Latitude
43.844013
Location Longitude
-93.089433
Nrc Rpt Num
1425565
Additional Nrc Report Numbers
1425735
Commodity Released Type
Natural Gas
Unintentional Release
24
Intentional Release
8037
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
No
Shutdown Explain
Pressure Was Lowered To Approximately 25 Pounds To Make Repairs.
Communication State Fed Ind
Yes
Party Initiated Communication
Operator
Ignite Ind
No
Upstream Action Taken
Valve Closure
Downstream Action Taken
Valve Closure
Num Pub Evacuated
0
On Off Shore
Onshore
Onshore State Abbreviation
Mn
Onshore Postal Code
55917
Onshore City Name
Not Within A Municipality
Onshore County Name
Freeborn
Designated Location
Milepost
Designated Name
15.51
Pipe Fac Name
La Crosse 12-Inch Loop
Segment Name
Mnb73202
Federal
No
Location Type
Operator-Controlled Property
Incident Area Type
Underground
Incident Area Subtype
Under Soil
Depth Of Cover
40
Other Underground Facilities
Yes
Crossing
No
Pipe Facility Type
Interstate
System Part Involved
Onshore Pipeline, Including Valve Sites
Item Involved
Tubing
Tubing Material
Carbon Steel
Tubing Type
Rigid
Installation Year
1993
Manufactured Year
1993
Material Involved
Carbon Steel
Release Type
Leak
Leak Type
Crack
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
294
Heat Damage Ind
No
Non Heat Damage Ind
No
Did Occur In Mca Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
88
Est Cost Intentional Release
29576
Est Cost Prop Damage
170000
Est Cost Emergency
0
Est Cost Other
0
Gas Cost In Mcf
3.68
Prpty
199664
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
841
Gas Flow In Pipe In Mcf
25000
Mop Psig
1000
Mop Cfr Section
192.619(A)(2)
Maop Established Date
1993-12-01 00:00:00
Maop Reversal Flow Ind
No
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
124080
Internal Inspection Ind
No
Unsuitable Mainline 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
The event was driven by a small leak that did not produce a noticeable pressure change. The cost of repair classified the event as a reportable incident.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Natural Force Damage
Cause Details
Temperature
Natural Force Type
Temperature
Temperature Subtype
Frost Heave
Nf Extreme Weather Ind
No
Nf Temperature Ind
Yes
Eqf Equipment Body Ind
Yes
Preparer Name
D**** C*******
Preparer Title
Sr. Pipeline Safety Engineer Ii
Preparer Email
D*************@n****.com
Preparer Telephone
4023987439
Authorizer Name
D**** C*******
Authorizer Title
Sr. Pipeline Safety Engineer Ii
Authorizer Telephone
4023987439
Authorizer Email
D*************@n****.com
Narrative
On march 11, 2025, at 1335 hours, a technician arrived on-site at the blooming prairie, mn branch line regulator station (mnr-0103) for regular maintenance and found bubbles coming up from below ground near pipeline facilities. A plan was developed to reduce pressure for investigation and evaluation of the cause of the leak. Third-party contractors were mobilized to preform excavation and repairs. After excavation, it was determined that a 1/4-inch nipple on the cbc01 valve body bleed riser had cracked and was leaking. On march 13, 2025, at 1240 hours, repairs were completed with new components and tested for leaks. Leak checks were performed at 100psig intervals as pressure was restored with no leaks identified. Field operations completed returning the mnb73202 pipeline back to regular operating configuration and pressure on march 13, 2025, at 1813 hours. Investigation concluded the body bleed riser was not sufficiently supported and due to years of ground freeze and thaws, the nipple body cracked causing the event. The replacement body bleed riser was installed with a rigid connection to prevent reoccurrence.
| Report Received Date | 2025-04-04 00:00:00 |
|---|---|
| Iyear | 2025 |
| Report Number | 20250033 |
| Supplemental Number | 40785 |
| Report Type | Supplemental Final |
| Operator Id | 13750 PHMSA Enforcement |
| Name | Northern Natural Gas Co |
| Operator Street Address | 1111 South 103rd Street |
| Operator City Name | Omaha |
| Operator State Abbreviation | NE |
| Operator Postal Code | 68124 |
| Time Zone | Central |
| Daylight Savings Ind | Yes |
| Location Latitude | 43.844013 Google Maps OpenStreetMap |
| Location Longitude | -93.089433 Google Maps OpenStreetMap |
| Nrc Rpt Num | 1425565 NRC Report How to search |
| Additional Nrc Report Numbers | 1425735 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 24 |
| Intentional Release | 8037 |
| 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 | No |
| Shutdown Explain | Pressure Was Lowered To Approximately 25 Pounds To Make Repairs. |
| Communication State Fed Ind | Yes |
| Party Initiated Communication | Operator |
| Ignite Ind | No |
| Upstream Action Taken | Valve Closure |
| Downstream Action Taken | Valve Closure |
| Num Pub Evacuated | 0 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Mn |
| Onshore Postal Code | 55917 |
| Onshore City Name | Not Within A Municipality |
| Onshore County Name | Freeborn |
| Designated Location | Milepost |
| Designated Name | 15.51 |
| Pipe Fac Name | La Crosse 12-Inch Loop |
| Segment Name | Mnb73202 |
| Federal | No |
| Location Type | Operator-Controlled Property |
| Incident Area Type | Underground |
| Incident Area Subtype | Under Soil |
| Depth Of Cover | 40 |
| Other Underground Facilities | Yes |
| Crossing | No |
| Pipe Facility Type | Interstate |
| System Part Involved | Onshore Pipeline, Including Valve Sites |
| Item Involved | Tubing |
| Tubing Material | Carbon Steel |
| Tubing Type | Rigid |
| Installation Year | 1993 |
| Manufactured Year | 1993 |
| Material Involved | Carbon Steel |
| Release Type | Leak |
| Leak Type | Crack |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 294 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Did Occur In Mca Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 88 |
| Est Cost Intentional Release | 29576 |
| Est Cost Prop Damage | 170000 |
| Est Cost Emergency | 0 |
| Est Cost Other | 0 |
| Gas Cost In Mcf | 3.68 |
| Prpty | 199664 |
| 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 | 841 |
| Gas Flow In Pipe In Mcf | 25000 |
| Mop Psig | 1000 |
| Mop Cfr Section | 192.619(A)(2) View CFR 49 §192 |
| Maop Established Date | 1993-12-01 00:00:00 |
| Maop Reversal Flow Ind | No |
| 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 | 124080 |
| Internal Inspection Ind | No |
| Unsuitable Mainline 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 | The event was driven by a small leak that did not produce a noticeable pressure change. The cost of repair classified the event as a reportable incident. |
| Employee Drug Test Ind | No |
| Contractor Drug Test Ind | No |
| Cause | Natural Force Damage |
| Cause Details | Temperature |
| Natural Force Type | Temperature |
| Temperature Subtype | Frost Heave |
| Nf Extreme Weather Ind | No |
| Nf Temperature Ind | Yes |
| Eqf Equipment Body Ind | Yes |
| Preparer Name | D**** C******* |
| Preparer Title | Sr. Pipeline Safety Engineer Ii |
| Preparer Email | D*************@n****.com |
| Preparer Telephone | 4023987439 |
| Authorizer Name | D**** C******* |
| Authorizer Title | Sr. Pipeline Safety Engineer Ii |
| Authorizer Telephone | 4023987439 |
| Authorizer Email | D*************@n****.com |
| Narrative | On march 11, 2025, at 1335 hours, a technician arrived on-site at the blooming prairie, mn branch line regulator station (mnr-0103) for regular maintenance and found bubbles coming up from below ground near pipeline facilities. A plan was developed to reduce pressure for investigation and evaluation of the cause of the leak. Third-party contractors were mobilized to preform excavation and repairs. After excavation, it was determined that a 1/4-inch nipple on the cbc01 valve body bleed riser had cracked and was leaking. On march 13, 2025, at 1240 hours, repairs were completed with new components and tested for leaks. Leak checks were performed at 100psig intervals as pressure was restored with no leaks identified. Field operations completed returning the mnb73202 pipeline back to regular operating configuration and pressure on march 13, 2025, at 1813 hours. Investigation concluded the body bleed riser was not sufficiently supported and due to years of ground freeze and thaws, the nipple body cracked causing the event. The replacement body bleed riser was installed with a rigid connection to prevent reoccurrence. |
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