The Hush was an option available on custom chassis built by E-One. First introduced in 1985, it moved the engine to the rear of the chassis. This rear engine configuration enabled a quieter cab (hence the name) and additional space, which in turn meant that firefighters rode inside the truck instead of on the rear step. The Hush option was available in the Cyclone and later Cyclone II cab.
The first Hush model built was sold to the Wyandanch Volunteer Fire Company in 1986.
The Hush engine setup was later offered in a mid-engine configuration starting in 1999. The engine was now mounted behind the cab in place of the pump panel. This configuration changed the pump mounting from mid-mount to rear-mount and was available on cabs like the Cyclone II, Quest and Typhoon.
The Hush setup was discontinued in 2015 in favor of the new Hush Series (HS).
In 2015, E-One re-introduced the rear-engine pumper to the industry. Now named the HS chassis, this configuration brought back flexibility to pump panel options and is available on the Cyclone or Quest cabs.