The lyrics of the song "Highwayman" by Johnny Cash (and sung by him and Willie Nelson, Waylon Jennings, and Kris Kristofferson) impart the idea that bodies are buried in Hoover Dam:
I was a dam builder across the river deep and wide
Where steel and water did collide
A place called Boulder on the wild Colorado
I slipped and fell into the wet concrete below
They buried me in that great tomb that knows no sound.
As the song indicates, the idea that bodies are buried in the damn has long been believed. IN fact, 96 workers died as the result of "industrial fatalities" (allowing the deceased's family to obtain compensation), plus another 42 cases that were called pneumonia, though are now thought to have been caused by high levels of carbon monoxide poisoning from working with motor vehicles boring the diversion tunnels.
However, the Bureau of Reclamation insists that no bodies are buried in that great tomb.
"The dam was built in interlocking blocks. Each block was five feet high. The smallest blocks were about 25 feet by 25 feet square, and the largest blocks were about 25 feet by 60 feet.
"Concrete was delivered to each block in buckets, eight cubic yards at a time. After each bucket was delivered, five or six men called 'puddlers' would stamp and vibrate the concrete into place, packing it down to ensure there were no air pockets in it.
"Each time a bucket was emptied, the level of concrete would raise from two inches up to six inches, depending on the size of the block. With only a slight increase in the level at any one time, and the presence of several men watching the placement, it would have been virtually impossible for anyone to be buried in the concrete."
Besides, if a body did somehow wind up in the concrete, it would have caused a serious weakness in the structural integrity of that particular block -- a major problem when holding back countless gallons of water.