Incident details
Operator, cause, commodity and consequences with raw source fields.
GTG incident on 2024-09-17 — TX
Operator
Southern Natural Gas Co
Cause
Equipment Failure
Commodity
Natural Gas
Program
GTG
Damage and Injuries
0 fatalities
0 injuries
Property damage (nominal)
$0
Incident datetime
2024-09-17 00:00 UTC
Report number
Location
TX
Narrative
On 8/18/2024 at approximately 9:36 pm the suction emergency shut down (esd) blow-off valve 001 at the selma compressor station inadvertently opened. At approximately 9:47 gas control took the station off-line. Location personnel responded and closed the valve at 10:48 pm. The station has a second suction esd blow-off valve. The local fire department closed the road to through traffic and stayed nearby until the event was under control. There were no evacuations and injuries. Investigation revealed that the root cause was a clogged orifice on the 1/2-inch supply gas line. The esd operated as designed and caused the valve to open once it stopped seeing the full pressure on the supply line that it was expecting to see.
Detailed record list
Report Received Date
2024-09-17 00:00:00
Iyear
2024
Report Number
20240109
Supplemental Number
40289
Report Type
Supplemental Final
Operator Id
18516
Name
Southern Natural Gas Co
Operator Street Address
1001 Louisiana St, Ste 1000 Suite 1000
Operator City Name
Houston
Operator State Abbreviation
TX
Operator Postal Code
77002
Time Zone
Central
Daylight Savings Ind
Yes
Location Latitude
32.525758
Location Longitude
-86.929988
Nrc Rpt Num
1408351
Additional Nrc Report Numbers
1408505
Commodity Released Type
Natural Gas
Unintentional Release
42197
Intentional Release
0
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
Communication State Fed Ind
Yes
Party Initiated Communication
Operator
Ignite Ind
No
Num Pub Evacuated
0
On Off Shore
Onshore
Onshore State Abbreviation
Al
Onshore Postal Code
36703
Onshore City Name
Selma
Onshore County Name
Dallas
Designated Location
Not Applicable
Pipe Fac Name
Selma Compressor Station
Segment Name
Sng South Mains
Federal
No
Location Type
Operator-Controlled Property
Incident Area Type
Aboveground
Incident Area Subtype
Typical Aboveground Facility Piping Or Appurtenance
Crossing
No
Pipe Facility Type
Interstate
System Part Involved
Onshore Compressor Station Equipment And Piping
Item Involved
Esd System, But Excluding Product Drain Lines And Tubing
Installation Year
Unknown
Manufactured Year
Unknown
Material Involved
Carbon Steel
Release Type
Other
Release Type Details
The Orifice On The Esd Pressure Line Became Clogged With Debris. Esd Supply Pressure Dropped Causing The False Opening Of The Vent Valve.
Class Location Type
Class 1 Location
Could Be Hca
No
Pir Radius
1044
Heat Damage Ind
No
Non Heat Damage Ind
No
Did Occur In Mca Ind
No
Est Cost Oper Paid
0
Est Cost Unintentional Release
101273
Est Cost Intentional Release
0
Est Cost Prop Damage
0
Est Cost Emergency
1000
Est Cost Other
0
Gas Cost In Mcf
2.4
Prpty
102273
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
970
Gas Flow In Pipe In Mcf
1900000
Mop Psig
1200
Mop Cfr Section
192.619(A)(2)
Maop Established Date
1998-12-07 00:00:00
Maop Reversal Flow Ind
No
Accident Pressure
Pressure Did Not Exceed Maop
Pressure Restriction Ind
No
Gas Required Odorized Ind
No
Pipeline Function
Transmission System
Scada In Place Ind
Yes
Scada Operating Ind
Yes
Scada Functional Ind
Yes
Scada Detection Ind
Yes
Scada Conf Ind
Yes
Accident Identifier
Scada-Based Information (Such As Alarm(S), Alert(S), Event(S), And/or Volume Or Pack Calculations)
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
Operator saw a sudden drop in pressure at selma c/s. Operations responded to the call out and discovered the vent valve open. Scada operated as designed and the control room responded as required.
Employee Drug Test Ind
No
Contractor Drug Test Ind
No
Cause
Equipment Failure
Cause Details
Malfunction Of Control/relief Equipment
Eq Failure Type
Malfunction Of Control/relief Equipment
Relief Valve Ind
Yes
Additional Improper Mntnce Ind
Yes
Preparer Name
B****** L** C*******
Preparer Title
Engineer - Pipeline Senior
Preparer Email
B***************@k***********.com
Preparer Telephone
2053257289
Local Contact Name
B**** P******
Local Contact Email
B************@k***********.com
Local Contact Telephone
2054608833
Authorizer Name
Z****** S* R*****
Authorizer Title
Director Engineering Codes And Standards
Authorizer Telephone
8329190774
Authorizer Email
Z**********@k***********.com
Narrative
On 8/18/2024 at approximately 9:36 pm the suction emergency shut down (esd) blow-off valve 001 at the selma compressor station inadvertently opened. At approximately 9:47 gas control took the station off-line. Location personnel responded and closed the valve at 10:48 pm. The station has a second suction esd blow-off valve. The local fire department closed the road to through traffic and stayed nearby until the event was under control. There were no evacuations and injuries. Investigation revealed that the root cause was a clogged orifice on the 1/2-inch supply gas line. The esd operated as designed and caused the valve to open once it stopped seeing the full pressure on the supply line that it was expecting to see.
| Report Received Date | 2024-09-17 00:00:00 |
|---|---|
| Iyear | 2024 |
| Report Number | 20240109 |
| Supplemental Number | 40289 |
| Report Type | Supplemental Final |
| Operator Id | 18516 PHMSA Enforcement |
| Name | Southern Natural Gas Co |
| Operator Street Address | 1001 Louisiana St, Ste 1000 Suite 1000 |
| Operator City Name | Houston |
| Operator State Abbreviation | TX |
| Operator Postal Code | 77002 |
| Time Zone | Central |
| Daylight Savings Ind | Yes |
| Location Latitude | 32.525758 Google Maps OpenStreetMap |
| Location Longitude | -86.929988 Google Maps OpenStreetMap |
| Nrc Rpt Num | 1408351 NRC Report How to search |
| Additional Nrc Report Numbers | 1408505 |
| Commodity Released Type | Natural Gas |
| Unintentional Release | 42197 |
| Intentional Release | 0 |
| 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 |
| Communication State Fed Ind | Yes |
| Party Initiated Communication | Operator |
| Ignite Ind | No |
| Num Pub Evacuated | 0 |
| On Off Shore | Onshore |
| Onshore State Abbreviation | Al |
| Onshore Postal Code | 36703 |
| Onshore City Name | Selma |
| Onshore County Name | Dallas |
| Designated Location | Not Applicable |
| Pipe Fac Name | Selma Compressor Station |
| Segment Name | Sng South Mains |
| Federal | No |
| Location Type | Operator-Controlled Property |
| Incident Area Type | Aboveground |
| Incident Area Subtype | Typical Aboveground Facility Piping Or Appurtenance |
| Crossing | No |
| Pipe Facility Type | Interstate |
| System Part Involved | Onshore Compressor Station Equipment And Piping |
| Item Involved | Esd System, But Excluding Product Drain Lines And Tubing |
| Installation Year | Unknown |
| Manufactured Year | Unknown |
| Material Involved | Carbon Steel |
| Release Type | Other |
| Release Type Details | The Orifice On The Esd Pressure Line Became Clogged With Debris. Esd Supply Pressure Dropped Causing The False Opening Of The Vent Valve. |
| Class Location Type | Class 1 Location |
| Could Be Hca | No |
| Pir Radius | 1044 |
| Heat Damage Ind | No |
| Non Heat Damage Ind | No |
| Did Occur In Mca Ind | No |
| Est Cost Oper Paid | 0 |
| Est Cost Unintentional Release | 101273 |
| Est Cost Intentional Release | 0 |
| Est Cost Prop Damage | 0 |
| Est Cost Emergency | 1000 |
| Est Cost Other | 0 |
| Gas Cost In Mcf | 2.4 |
| Prpty | 102273 |
| 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 | 970 |
| Gas Flow In Pipe In Mcf | 1900000 |
| Mop Psig | 1200 |
| Mop Cfr Section | 192.619(A)(2) View CFR 49 §192 |
| Maop Established Date | 1998-12-07 00:00:00 |
| Maop Reversal Flow Ind | No |
| Accident Pressure | Pressure Did Not Exceed Maop |
| Pressure Restriction Ind | No |
| Gas Required Odorized Ind | No |
| Pipeline Function | Transmission System |
| Scada In Place Ind | Yes |
| Scada Operating Ind | Yes |
| Scada Functional Ind | Yes |
| Scada Detection Ind | Yes |
| Scada Conf Ind | Yes |
| Accident Identifier | Scada-Based Information (Such As Alarm(S), Alert(S), Event(S), And/or Volume Or Pack Calculations) |
| 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 | Operator saw a sudden drop in pressure at selma c/s. Operations responded to the call out and discovered the vent valve open. Scada operated as designed and the control room responded as required. |
| Employee Drug Test Ind | No |
| Contractor Drug Test Ind | No |
| Cause | Equipment Failure |
| Cause Details | Malfunction Of Control/relief Equipment |
| Eq Failure Type | Malfunction Of Control/relief Equipment |
| Relief Valve Ind | Yes |
| Additional Improper Mntnce Ind | Yes |
| Preparer Name | B****** L** C******* |
| Preparer Title | Engineer - Pipeline Senior |
| Preparer Email | B***************@k***********.com |
| Preparer Telephone | 2053257289 |
| Local Contact Name | B**** P****** |
| Local Contact Email | B************@k***********.com |
| Local Contact Telephone | 2054608833 |
| Authorizer Name | Z****** S* R***** |
| Authorizer Title | Director Engineering Codes And Standards |
| Authorizer Telephone | 8329190774 |
| Authorizer Email | Z**********@k***********.com |
| Narrative | On 8/18/2024 at approximately 9:36 pm the suction emergency shut down (esd) blow-off valve 001 at the selma compressor station inadvertently opened. At approximately 9:47 gas control took the station off-line. Location personnel responded and closed the valve at 10:48 pm. The station has a second suction esd blow-off valve. The local fire department closed the road to through traffic and stayed nearby until the event was under control. There were no evacuations and injuries. Investigation revealed that the root cause was a clogged orifice on the 1/2-inch supply gas line. The esd operated as designed and caused the valve to open once it stopped seeing the full pressure on the supply line that it was expecting to see. |
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