Emergency Service Unit
An emergency service unit (ESU), alternatively emergency service detail (ESD) or emergency service squad (ESS), is a type of unit within an emergency service, usually police, that is capable of responding to and handling a broader or more specific range of emergencies and calls for service than regular units within their organization, such as rescue, emergency management, and mass casualty incidents. They are similar to police tactical units, fire department technical rescue, and incident response teams in other emergency services and organizations, and often have similar or overlapping roles; the term is also used synonymously for these units, or as a catch-all for units that combine multiple disciplines and roles under one banner.