Abstract: On February 22, 2002, Employee #1 was using the radio-frequency heat sealer machine to adhere rubber boots to fisherman pants. She was straightening the pants on to the board because it was wrinkled. Suddenly, the die inadvertently came down, crushing her left thumb. (The employee stated that she had not operated the foot control.) After the incident, she was transported to and treated at Kaiser Permanente - Baldwin Park Hospital. Prior to the incident, Employee #1 was taught how to operate the machine, how to put the pants in, which button to press, and which button to lift the die. However, the machine did not have a point of operation guard.