Abstract: At 1:00 p.m. on March 24, 2017, an employee was working with three other coworkers that were hydro-testing some tubing in a well. The crew installed a circulating head with a PGSR rubber to contain the gasses from the well but first installed one that was too large. They pulled it from the well and replaced it with a smaller version; however, one of the coworkers opened the slips while the employee was holding onto the API ring with their left hand. The coworker lowered the elevator and the employee had their thumb pinched and crushed between the API ring and the elevator. The employee sustained a partial amputation of their left thumb.