Abstract: At 10:55 a.m. on December 12, 2022, an employe who worked as a Dump Truck Driver for a concrete and masonry company, and Coworker #1 (Shop Mechanic) were working in the mechanics shop. According to Coworker #2 (Owner) there was not enough field work for the employee to complete, so he instructed him to come into the shop and clean or perform any preventative maintenance necessary on his 2016 Peterbuilt Model 567 dump truck. According to Coworker #1, the employee wanted to weld a strip of metal measuring approximately 2-1/2 inches wide by 88-1/4 inches long underneath the tailgate of the truck. According to Coworker #1 the employee stated that the metal strip would block the rock and debris that was getting stuck between the tailgate and the bumper causing it to fly out every time a bump was struck. The employee pulled the truck into the garage. He raised the pneumatically powered tailgate, which was raised when the truck was turned off. Once the truck is turned off, air slowly dissipates from the compressor and the tailgate slowly closes which takes approximately 50 minutes. The employee and Coworker #1 used a 7-foot wooden railing to hold up the tailgate. They lodged the railing between the bottom of the truck bed and the tailgate. According to Coworker #1, while they were working on the truck the wooden railing had been used as a brace for approximately one hour and 20 minutes. Coworker #1 stated that he went to the bathroom and while washing his hands he heard three loud bangs. When he came back into the shop, he saw that the tailgate had come down and the employee was on the ground visibly injured. He also commented that the railing had snapped in half. The employee died at the jobsite.