HICS is simply a standardized approach to managing complex incidents. Each hospital that adopts this process is agreeing to follow common principles and use standardized terminology in the event of a large-scale emergency or event. The principles of HICS come from the Incident Command System (ICS) developed for managing wildland fires in California in the 1970s. Wildland fires use resources from many different organizations, and those folks didn’t all do things the same way. ICS standardized the response to fires, which made everyone more efficient and safer.
Even within a single hospital, each department might do things differently. Just like during a wildfire, HICS allows the hospital to standardize its approach to an event globally, even if each department does things their own way during normal operations. In the fire service, adopting ICS led to a lot of command structure standardization across individual fire departments, which is also beginning to happen in the hospital industry. This is good; people understand HICS concepts better if they are using them all the time.
ICS has been around since the 1970s. HICS became popular about 20 years later, mostly in areas familiar with wildland fires and comfortable with the use of ICS. After the 9/11 attacks, the federal government implemented the National Incident Management System (NIMS), which incorporates ICS. Since then, HICS has become much more common across the nation and worldwide.