Chevron Refinery Fire as investigated by CSB.pptx

CSB Report on Chevron Refinery Fire

1. SAFETY TALK CHEVRON RICHMOND REFINERY PIPE RUPTURE AND FIRE

2. INTRODUCTION This case study describes the sudden release of light gas oil and subsequent fire due to rupture of pipeline that occurred on August 6, 2012 at Chevron Richmond Refinery, California USA The Vapour cloud engulfed 18 employees including firefighters who escaped just before ignition from the site within two minutes. Total 6 personnel injured during emergency response efforts.

3. Incident Incident occurred in Crude Distillation unit where 8” sidecut line of Light Gas Oil service got ruptured due to sulphidation corrosion which lead to subsequent release of gas oil and vapour cloud fire. CRUDE DISTILLATION UNIT COLUMN

4. Sequence of Incidents Dropwise leak of gas oil identified by one of the operator at around 3:30 PM on 6 th August 2012 As there was not any valve in between column and leak portion, it was decided to clamp the leak portion. Fire team took all preparatory action for probable emergency scenario

5. Sequence of Incidents It was decided to remove insulation first to assess the leak situation. Initially fire team used pike pole to remove insulation from ground which might have damaged already thinned CS pipeline. Later on scaffolding made and two firemen tried removing aluminum sheathing using hook. While maximum aluminum portion was removed, oil socked insulation caught fire as vapour was continuously releasing from leaky portion. Fire men extinguished the flash fire using fire hose already prepared for emergency action. Now it was decided to remove remaining insulation with the force of water jet from distance. Insulation was removed by direct water streams but significantly worsened the leak. Gas oil was now spraying from pipe. Then only, it was decided to shutdown

6. Consequences Hot and dense vapour cloud started spreading in the area engulfing 19 fire fighters & plant personnel. Two minutes after the large vapour cloud formed , the light gas oil ignited. By that time, 18 persons escaped and one fire fighter got caught in fire tender ( engulfed in fire ball). Later on he also escaped uninjured.

7. FINDINGS Pipeline got thinned because of sulphidation corrosion Side cut pipe line was inspected in 2002, and it was assessed that it would fail in 2012 due to accelerated thinning in the piping section. But it was not replaced. In 2009 Chevron experts recommended that every segment of high risk CS piping be inspected for corrosion. But it was not done. During 2011 M&I , Inspection was done at few segments including side cut line and found significant thinning. Based on recommendation few segments changed but not all, as management did not considered it immediate danger and decided to keep pipe in service till next M&I in 5 years

8. FINDINGS Leak Mitigation and discovery attempt worsened leak Post incident metallurgical analysis indicates that the fire fighter pike pole used in attempt to remove insulation may have stabbed through the highly thinned pipe. Had it been known to plant personnel/fire fighters about thinning of pipeline, all attempts to put clamp would not have done. They might have gone for shutdown.

9. LESSONs LEARNT Each and every segment of the piping should have been inspected to assess corrosion/thinning Thinning pipeline should have been replaced much earlier with an inherently safer corrosion resistant alloy Shutdown of the unit should have been initiated by timely assessing the probable emergency due to massive leak

10. THANKS