Abstract: On October 28, 2002, several employees were working at an oil rigging jobsite in Santa Fe, CA assisting in the process of retrieving oil for distribution. The oil was flowing from a well through a 2-inch, 15,000-pound flow line to a manual choke manifold, 22/64 choke, to a sand separator and then to sales. For some reason, the pressure had been dropping approximately 15-pounds to 25-pounds every hour. This pattern continued into the start of the night shift, having dropped a total of 400-pounds by 6:00 p.m. Further, the flow line and both sides of the manual choke manifolds became clogged, not allowing any natural gas to flow. A flow cross "T" was installed, containing a manual "ACR" (hydraulically operated) valve on each side near the center. On the east side of the flow cross "T" there was a continuous connection, extending to the ground level, of two additional 2-inch, 15,000-pound flow lines; Chic-san swivel connection with hammer connection unions; and pump truck. On the west side of the flow cross "T" a 2-inch, 15,000-pound flow line was extended in the direction of the hydraulic choke manifold, but was not connected. In addition, two manual valves, on each side of the center of the flow cross "T" were open, with only the "HCR" (hydraulically operated) valves being closed. Employee #1 began breaking the hammer connection at the Chic-san swivel in order to add another 2-inch, 15,000-pound flow line to the north side of the manual choke manifold. This process was meant to provide flow back through the manual choke manifold and up through the riser flow line to the second wing on the east side. For some reason, the hammer connection union at the Chic-san swivel connection was broken and unthreaded, causing a loud bang to occur. The 2-inch, 15,000-pound flow line riser kicked and was bent. Pressurized natural gas was violently released, striking Employees #1 and #2.