 The use of pneumatic caissons in skyscraper foundations grew more advanced; in the construction of the 1908 Manhattan Municipal Building they were successfully sunk below the surface, with specially conditioned workers operating in shifts with constant medical support.New technologies were also introduced within the buildings.Fast Otis elevators, powered by electricity rather than steam-driven hydraulics, began to be installed in skyscrapers, with Ellithorpe safety air cushions protecting the passengers in the case of failure.