NORTH DAKOTA PIPELINE COMPANY LLC

Incident Narrative

AN EXPLOSION/FIRE OCCURRED AT THE ALEXANDER STATION RESULTING IN A RELEASE OF APPROXIMATELY 2 GALLONS OF CRUDE OIL (9 TOTAL GALLONS REPORTED INCLUDES 7 ADDITIONAL GALLONS OF DRAIN DOWN) AND CAUSING AN INJURY TO A CONTRACT EMPLOYEE. THE INCIDENT OCCURRED WHEN WELDERS WERE WELDING ON A FLANGE AND A FOREMAN'S PLUG BLEW. A METALLURGICAL ANALYSIS WAS CONDUCTED AND CONFIRMED POROSITY AS A MANUFACTURING DEFECT. THE ANALYSIS CONCLUDED THAT THE FLAME FROM WELDING IGNITED VAPORS THAT HAD LEAKED THROUGH THE LARGE POROSITY HOLES IN THE FOREMAN PLUG, THE FLAMES TRAVELED BACK THROUGH THE PLUG IGNITING VAPORS IN THE PIPE WHICH CAUSED THE PLUG TO BE EJECTED. THE THIRD PARTY CONTRACTOR WAS TAKEN TO A MEDICAL FACILITY FOR TREATMENT. CONTRACTOR WAS TREATED AND RELEASED. 10/07/2016 IN DISCUSSIONS WITH THE PLUG'S MANUFACTURER FOLLOWING THIS INCIDENT, NDPL DISCOVERED THAT THE MANUFACTURER REVISED ITS SPECIFICATIONS REGARDING USE OF THE FOREMEN'S PLUG AFTER NDPL'S REGULAR ANNUAL REVIEW OF MANUFACTURER'S SPECIFICATIONS IN NOVEMBER 2013, AND PRIOR TO NDPL'S REGULARLY SCHEDULED ANNUAL REVIEW OF SAID SPECIFICATIONS IN NOVEMBER 2014, RECOMMENDING AGAINST USE IN THIS APPLICATION. NDPL MAINTAINS THE POROSITY (MANUFACTURING DEFECT) DISCOVERED DURING THE INVESTIGATION OF THIS INCIDENT WAS THE ROOT CAUSE OF THE INCIDENT. NDPL HAS AGREED TO UPDATE THE 7000-1 FROM EQUIPMENT FAILURE TO INCORRECT EQUIPMENT AFTER REVIEW WITH PHMSA ACCIDENT INVESTIGATOR. BASED ON THE CHANGE TO THE MANUFACTURER'S INSTRUCTION, NDPL HAS REVISED ITS PROCEDURE AND NO LONGER INCLUDES THE USE OF A FOREMEN'S PLUG IN THIS APPLICATION.