UNITED STATES
DEPARTMENT OF LABOR

At 2:30 p.m. on October 27, 2020, Employee #1, Coworkers #1 and #2, and their su pervisor, divers employed by a civil engineering construction company, were enga ged in a diving operation at a lake dam. They were assigned to conduct inspecti ons and repairs to several gates and chains. During a solitary dive with an umb ilical supplying breathing gas and video, Employee #1 climbed down a long ladder to the water's surface. He then descended into the water, sliding down the cha in with his right hand while feeling the side of the dam face with his left hand to guide his way down. At a depth of approximately 15 to 20 feet, his left han d came into contact with a 10-inch hole in the dam's face that led into a Pensto ck Pipe. Differential pressure caused the employee's left arm to be sucked into the pipe up to his shoulder. He cried out and then went silent and unresponsiv e. The dive supervisor attempted several times to communicate with Employee #1 but received no response. The supervisor instructed Coworker #1, the backup div er, to go into the water. Coworker #1, after reaching Employee #1, reported tha t Employee #1 remained unresponsive with no signs of breathing. Coworker #1 was unable to free him from the pipe. Several dam employees were called to the sce ne, and one of the dam operators closed a valve which released the diver from th e pipe. Coworker #1 brought Employee #1 to the water's surface, where he was at tached to the emergency retrieval system, removed from the water, and placed on the main deck where emergency medical technicians were standing by. Employee #1 was transported to the hospital, where he was declared dead. The subsequent in vestigation reported that mechanical asphyxiation may have been the cause of dea th. At no time had Employee #1 lost air.