The accident happened at the company's premises in the Weyarn municipality, southeast of Munich, on Tuesday morning, Bavarian police said in a statement.
One of the men was working in a water-filled drain, and two colleagues who had lost contact with him climbed in to help him. There was no further sign of life from the three. Firefighters and rescuers were called to the scene. Divers were unable to locate the three missing men immediately because of high water. Their bodies were recovered only when the water level was lowered by "technical means," police said.Police were working to determine how the accident happened.