On August 12, 2016, hot work was being conducted by a contractor at a crude oil terminal on a section of pipe that contained residual crude oil. Using an isolation device, the pipe segment was plugged on both ends by a sub-contractor (hired by the primary contractor). During the welding operation on the inside surface of a flange, vapor inside the pipe gathered between two of the installed isolation devices and ignited. The ignition caused a build-up in pressure, which led to a violent explosion at either end of the isolated pipe, resulting in burn injuries to seven (7) workers.
NOTE: A contractor issued the HW permit to the contractor performing the HW. The report states this was done on behalf of the host.