Abstract: At 2:30 a.m. on June 24, 2014, an employee was riding as a passenger along with three other employees on the Marsh Master, transporting material and equipment between poles 199 and 197. The driver followed their planned route when they encountered a creek. The route they chose was not passable, so another was selected. As the driver attempted to cross the creek, it struck a submerged tree that they did not see, causing the Marsh Master to roll over. Three of the four employees swam away from the Marsh Master as it rolled over, but one employee could not swim. Holding onto the ROPS of the Marsh Master as it rolled over, he was pinned by the legs to the creek bed. The employees were not wearing, nor were they provided with, personal floatation devices. The employee was killed by drowning.