EXXONMOBIL PIPELINE CO
hazardous_liquid Incident — — February 20, 2011
Incident Information
| Incident Date | February 20, 2011 |
| Operator | EXXONMOBIL PIPELINE CO |
| Commodity | HVL OR OTHER FLAMMABLE OR TOXIC FLUID WHICH IS A GAS AT AMBI |
| Pipeline Type | hazardous_liquid |
Location
| State | |
| Coordinates | 29.84722, -94.90222 |
Cause
| Cause | EQUIPMENT FAILURE |
| Subcause | MALFUNCTION OF CONTROL/RELIEF EQUIPMENT |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $500 |
| Emergency Response | $500 |
| Other Costs | $0 |
Location Map
Incident Narrative
"EMPCO EXPERIENCED A RELEASE ON AN ITT PRESSURE SWITCH IN ETHYLENE SERVICE. THE CAUSE OF THE INCIDENT APPEARS TO BE THE FAILURE OF THE CAP SCREWS THAT SECURE THE TOP OF THE SWITCH TO THE SWITCH BODY. PRESSURE AT THE TIME OF THE FAILURE WAS 1233 PSI, WELL WITHIN THE SAFE OPERATING RANGE OF THE DEVICE. EMPCO IS WORKING WITH THE SWITCH MANUFACTURER TO DETERMINE WHY THE CAP SCREWS FAILED. THIS INCIDENT OCCURRED AT A MANNED FACILITY, OPERATOR WAS ABLE TO ISOLATE THE SWITCH QUICKLY. METALLURGY TESTING INDICATED THE SWITCH ASSEMBLY FAILED DUE TO ENVIRONMENTALLY INDUCED HYDROGEN EMBRITTLEMENT OF THE SOCKET HEAD CAP SCREWS. THE PRESENCE OF HYDROGEN IS ATTRIBUTED TO CORROSION OF THE ZINC PLATING AND SUBSEQUENTLY OF THE 410SS BASE METAL. THE CORROSION OF THE PLATING AND BASE METAL IS ATTRIBUTED TO THE OPERATING ENVIRONMENT. ANNEALED STAINLESS STEEL CAP SCREWS WILL BE USED AS REPLACEMENTS."
About This Pipeline Incident
Pipeline incident data is reported to the Pipeline and Hazardous Materials Safety Administration (PHMSA). All significant incidents involving fatalities, injuries, or property damage over $50,000 must be reported.