THE DOW CHEMICAL COMPANY

Incident Narrative

ON OCTOBER 14TH, 2021 AT 1140 HOURS, OPERATIONS REPORTED DISCOVERY OF BUBBLES AND GAS ODOR IN CORRIDOR R. ON THE SAME DAY AT 1255 HOURS, OPERATIONS REPORTED THAT THE LEAK WAS COMING FROM DPL-265 (FUEL GAS LINE). AT 1425 HOURS, OPERATIONS BLOCKED IN THE DPL-265 FUEL GAS LINE. AT 1437 HOURS, OPERATIONS BEGAN VENTING DOWN DPL-265 AT A STARTING PRESSURE OF 565 PSIG. ON OCTOBER 15TH AT 0013 HOURS, DPL-265 WAS DEPRESSURED AND VENTING WAS COMPLETED. ON THE SAME DAY AT 0700 HOURS, OPERATIONS DETERMINED THAT THE BUBBLES AND GAS LEAK WAS STILL ONGOING AND BEGAN FURTHER LEAK IDENTIFICATION EFFORTS. AT 1500 HOURS, THE BUBBLE GAS SAMPLES CAME BACK FROM THE LAB INDICATING THAT THE LEAK GAS WAS PROPYLENE. ON OCTOBER 16TH AT 0900 HOURS, OPERATIONS CONFIRMED WITH A THIRD GAS SAMPLE AND COMPLETED PROBING ACTIVITIES THAT THE LEAK WAS FROM DPL-245. THE TEAM THEN BEGAN WORKING WITH AFFECTED PLANTS TO DEVELOP SHUTDOWN OF PIPELINE THAT WOULD MINIMIZE ENVIRONMENTAL IMPACT. ON OCTOBER 20TH AT 0630 HOURS, OPERATIONS BEGAN TO SHUT DOWN THE DPL-245 PIPELINE. AT 0730 HOURS, THE BUBBLES AT THE LEAK SITE STOPPED. AT 0800 HOURS, FLARING BEGAN AT A STARTING PRESSURE OF 290 PSIG ON THE PIPELINE. ON OCTOBER 22ND, THE PIPELINE PRESSURE WAS AT 0 PSIG. THE EMERGENCY RESPONSE COST WAS $0, EMERGENCY RESPONDERS ARE DOW EMPLOYEES WHO ARE ASSIGNED THIS DUTY AS A PART OF THEIR DAILY RESPONSIBILITY. THERE IS NO ADDITIONAL COST INCURRED. THE PIPE FAILED DUE TO A NON-METALLIC INCLUSION ' A STEEL MAKING DEFECT ' ENTERING THE WELD FUSION LINE DURING PIPE MANUFACTURING ' A PIPE MAKING IMPERFECTION (HOOK CRACKS) WHICH CANNOT BE TRADITIONALLY DETECTED ' AND BEING EXPLOITED DURING SERVICE. NON-METALLIC INCLUSIONS DO NOT BEAR STRESSES BUT ARE TYPICALLY NOT CONSIDERED AN ISSUE AS THE INCLUSIONS ARE NORMALLY ALIGNED WITH THE HOOP STRESS. DUE TO THE INCLUSIONS BEING TURNED DURING THE WELDING PROCESS, THE INCLUSIONS WERE NORMAL TO THE HOOP STRESS PLANE AND COULD NOT SUPPORT THE STRESSES OF OPERATION. ADDITIONAL TO THESE WAS THE PRESENCE OF PLATE OFFSET WITH AN ENTRAPPED INCLUSION. THE PLATE OFFSET RESULTED IN A SKIP OF THE ID SCARFING TOOL DURING PIPE MANUFACTURING LEADING TO A STRESS RISER WHICH POTENTIALLY ACTED AS THE INITIATION SITE FOR A THROUGH-WALL LEAK PATH. IT SHOULD BE NOTED THAT THERE WAS NO DIRECT ID TO OD LEAK PATH FOUND. RATHER, THE CRACKING MOVED LONGITUDINALLY ALONG THE WELD SEAM IN AN ATTEMPT TO CONNECT LINEAR INCLUSIONS MAKING THE LEAK PATH VERY NARROW AND DIFFICULT TO DETECT. GIVEN THE TIGHT AND WELL DEFINED FEATURES OF THE CRACK PATHS, IT IS EXPECTED THAT THE LEAK PATH WAS NOT THROUGH-WALL MUCH, IF AT ALL, EARLIER THAN DETECTED BY THE WALKOUT. MECHANICAL TESTING OF THE WELD, IN CONJUNCTION WITH THE EXHIBITED MICROSTRUCTURE, INDICATE THAT THE OVERALL WELD IS BOTH STRONG AND TOUGH. THE RISK OF A RUPTURE, EVEN AT MAXIMUM ALLOWABLE OPERATING PRESSURE, IS HIGHLY UNLIKELY. REPORT DATE 16-OCT-2021 SAMPLE ID 622568 LAB2118764 PLANT NAME . . . . .: STRATTON_R SAMPLE NAME . . . .: PIPELINE LEAK DATE SAMPLE TAKEN .: 16-OCT-2021 09:01:36.00 -------------------------------------------------------------------------------- | TEST |R | COMPONENT NAME | RESULT |ST | -------------------------------------------------------------------------------- |REF_GAS |N | METHANE | 0.009 %MOLE |REF_GAS |N | PROPANE | 0.038 %MOLE |REF_GAS |N | PROPYLENE | 11.855 %MOLE |REF_GAS |N | CARBON DIOXIDE | 0.109 %MOLE |REF_GAS |N | OXYGEN/ARGON | 16.047 %MOLE |REF_GAS |N | NITROGEN | 62.526 %MOLE