Abstract: At 1:45 p.m. on March 31, 2010, Employee #1 and his colleagues were in the process of breaking down and putting away the equipment after they just completed a cleanout job of an oil well bore earlier. Employee #1 was closing a valve when he opened the adjacent valve, the wrong valve, releasing the pressure. The released pressure forced an iron Chiksan swivel joint to swing and contact Employee #1's left arm. The impact of the iron joint broke Employee #1's left arm radial bone. Employee #1 was standing in front of the valve when he was injured. The Chiksan swivel joint, the valves, and equipment are parts of a coil tubing service/oil well servicing an EMI trailer/truck unit. The Chiksan swivel joint connected to the valve was about 5 to 5.5 feet from the ground. Employee #1 was standing in front of the valve and was the only injured employee at the scene of the accident. Employee #1 was employed full time by Schlumberger Company who provides work related to oil well including oil wells bore cleanout and drilling. The accident occurred at the Occidental oil lease in Taft, CA. The employer reported the accident to DOSH on April 14, 2010.