DESPITE, AMONG VARIOUS OTHER DIFFICULTIES, BEING THE LARGEST CONCRETE STRUCTURE EVER BUILT AT THE TIME, over one hundred worker deaths, and challenging weather (the average daytime high during the summer of ’31 was 119.9°F), the Hoover Dam was delivered to the federal government by Six Companies, Inc.11A conglomeration of six pre-existing construction outfits, Six Companies was formed purely for the purpose of constructing the dam over two years ahead of schedule. Employing an arch-gravity design, the Hoover Dam’s convex side extends upstream into the reservoir, where the water compresses the dam structure and pushes it into the ground. The entire flow of the Colorado flows through the Hoover turbines (via the iconic penstock towers), producing an average of 4.2TWh per year since 1940 and it sees more than a million tourists annually.
In total, deaths associated with the dam construction amounted to 112—though this figure does not include workers who died from “pneumonia22Some allege the infection was used as a coverup for those who actually died of carbon monoxide poisoning from operating vehicles inside of tunnels.“. Of the 112, only 96 are deemed “official” by the Bureau of Reclamation, as deaths like J. G. Tierney, who drowned after falling into the Colorado 20 December 1922 have been deemed to be outside the scope of the construction project. Tierney was the first of the 112 aforementioned deaths; the last died in a fall on 20 December 1935: his son Patrick W. Tierney.