Abstract: At approximately 9:22 a.m. on April 22, 2016, Employee #1 entered through a manhole and was working in a confined space. Employee #1 had climbed down a ladder and entered the 12 ft deep manhole to read markings on a mixer plate. In the confined space, Employee #1 began to read markings on the mixer plate to Employee #2. Employee #1 then stood up and climbed a couple of ladder rungs, but lost consciousness and fell from the ladder. Employee #2 radioed for help, climbed down the ladder and checked on Employee #1. As Employee #2 was about a fourth of the way down the ladder, he also lost consciousness and fell from the ladder. Both employees died in an oxygen deficient atmosphere with displacing gases that included carbon dioxide.