An investigative communication notes that "mechanical integrity programs at refineries repeatedly emphasize inspection strategies rather then the use of inherently safer design to control the damage mechanisms that ultimately cause major process safety incidents." Regarding the similarity of this accident to others, it is also noted that "while sulfidation is a well-known damage mechanism at refineries that requires regular inspection and monitoring, the segment that failed has no record of ever being inspected."

NOTE: This record is based upon an investigative report and related communications and will be updated, as appropriate, when additional investigative reports are completed, released and reviewed. Additional details regarding mechanical integrity programs and procedures in place at the time of the accident are expected.