Emergency response
Emergency response means responding immediately at the BLS or ALS1 level of service to a 911 call or the equivalent in areas without a 911 call system. An immediate response is one in which the ambulance entity begins as quickly as possible to take the steps necessary to respond to the call.
Source
42 CFR § 414.605
Scoping language
As used in this subpart, the following definitions apply to both land and water (hereafter collectively referred to as ground) ambulance services and to air ambulance services unless otherwise specified: