Abstract: On December 13, 1993, Employee #1 and a helper were changing chokes on a gas line located at well #SS-7 in the employer's natural gas storage field. The choke fits between two sections of pipe that are bolted together with a flange. So that the old choke can be removed and a new one inserted, some bolts are removed and others loosened so the pipe flanges can be spread apart with a pry bar. Employee #1 was changing the choke while his helper held the flanges apart with a pry bar. While preparing to straighten a gasket inside the pipe flange with a piece of welding rod, Employee #1 slipped on some mud on the ground and fell forward. He put his arms out to regain his balance, causing one of his fingers to go between the two pipe flanges. At that moment, the pry bar also slipped out, causing the two pipe sections to close together and crush part of Employee #1's left index finger. No blocking device had been used to prevent the two pipe sections from coming together inadvertently.