Abstract: At approximately 3:00 p.m. on March 6, 2011, ten workers were performing maintenance on a 180-ft process tower. Employee #1 and a coworker were doing site preparation to install a 20-inch nozzle on the tower at the 100-ft level. Five of the ten workers were at the very top of the tower preparing to do confined space entry for internal tower work. Three workers were at the ground level doing structural work. The personal hydrogen sulfide (H2S) meters on Employee #1 and his coworker started to alarm at the same time. The coworker called out on his radio, alerting the other workers, including a ground level supervisor, of the encounter with the H2S. Immediately, all workers on the tower began to descend from their respective levels. Employee #1 and his coworker began descending from the 100-ft level and encountered an increasingly dangerous atmosphere. As those workers at the very top began to descend, their personal meters began alarming. The ground level superintendent suspected that the H2S was at a higher concentration near the 100-ft level and called out on the radio for those workers that were in the process of descending from the very top to go back up. Employee #1 and his coworker began to lose consciousness and fell from their respective locations. Employee #1 fell down to the deck near the 100-ft level. His coworker slid down the ladder cage that connected the deck near the 100-ft level to the deck below. The coworker slid down into a more breathable atmosphere, sustaining bruising but survived with minor injuries. Employee #1 passed out from the H2S gas and suffered blunt trauma to his head, resulting in his death.