Abstract: At 8:15 a.m. on December 21, 2018, Employee #1 and a coworker, employed by an electrical contractor, were installing interior electrical systems at a theme park expansion. Employee #1 was tasked with retrieving a 5-inch by 5-inch square junction box and knocking out a 1-inch hole using a hydraulic knockout tool, a Greenlee Hydraulic Punch Driver, so that his coworker, a journeyman electrician, could install the junction box in the attic. The employee asked the journeyman electrician if he could use the knockout set and then resumed work. However, he did not set up the tool properly. The cup was installed upside-down, and when he increased the hydraulic pressure, expecting it to cut a 1-inch hole in the junction box, there was too much pressure on the die. The die fractured, and a metal piece of the die was propelled through the air and struck his left eye. Employee #1 was transported to the hospital, where he was admitted and treated for a laceration to the eye.